Historical Posts Archives - Page 31 of 378 - Mount Washington Observatory

August 2018

The Science of Auroras

2018-08-08 06:18:51.000 – Christopher Hohman, Weather Observer/Staff Meteorologist

One of my personal favorite weather phenomenon here on the summit of Mount Washington, is one I haven’t actually observed yet! For the past few years I have been incredibly interested with quantum mechanics (A very fancy term that pretty much means the physics of how very small objects, like atoms and their electrons, move and/or interact!) in the atmosphere. A very beautiful phenomenon occurs at the atomic level that really interests me is the Aurora Borealis! In this blog I wanted to give just a brief explanation of how that works, and why there’s sadly a low chance we’ll see any this summer.

It starts with the sun. Highly energized particles are released from the sun, and are sent whizzing toward the earth at the speed of light. This energy takes about 8 minutes to hit the Earth (8 light minutes). These particles will first hit the Earth’s magnetic field. Some of it won’t actually reach the Earth’s atmosphere, but the rest of it is funneled toward the poles, and dumped into our atmosphere (Hence why we only see the Aurora at the poles!).

This is where the fun begins. Once that energy gets past the magnetic field, it is then absorbed by various gases in our atmosphere. These gases are typically Nitrogen, and Oxygen (The two most abundant gases in our atmosphere). When the energy is absorbed, it actually excites the electrons in the Oxygen and Nitrogen atoms. The electrons stay in the excited state briefly, then (to put in layman’s terms) un-excite themselves. When that happens, visible light waves are admitted by the atom. Or, as we like to call it, the Aurora!

I know I’m blasting you with physics right now, but there’s one last piece of this that really interests me. The Aurora normally only comes in Green or Red. Sometimes it’ll come in Blue or Violet, but that’s normally very hard to see. Why only these colors? This is due to the fact that Oxygen and Nitrogen can only absorb specific amounts of energy from the sun. Not too much, not too little, only specific amount to excite their electrons. Because of this, the atoms can only admit specific colors. Any other color you may see is just the colors blending together!

As I stated before the sun’s energy is where this whole process even starts. Right now we are heading into what’s called a solar minimum. I could have an entire blog post about what that is, but essentially it means the sun is not as active. Because of this the sun isn’t blasting us with bursts of high energy particles as often. So, unfortunately, it’s unlikely we’ll have a strong aurora to reach New England this summer.

Chin up though! There’s still plenty of awesome weather to observe in the meantime. I hope you enjoyed my blog, and even learned a few things from it! If you’re wondering how intense the Aurora will be tonight, just head on over to this website: http://www.aurora-service.org/aurora-forecast/

Christopher Hohman, Weather Observer/Staff Meteorologist

July Climatology

2018-08-04 19:09:40.000 – Adam Gill, Weather Observer/IT Specialist

As many people here in New England know, July was a very warm month across the Northeastern US. Mount Washington was no exception, though many sought refuge from the oppressive heat and humidity in the valleys since we are usually 20-30 degrees colder. We started off the month with a significant heat wave, nearly breaking our all-time record high of 72°F. We set record highs on the 1^st (68°F), 4^th (70°F), and the 5^th (71°F). The last time the summit had seen 70°F was in 2006 and then 71 was the warmest temperature we have seen since we had last tied our all-time record high on June 26^th, 2003.

So how does this July stack up to the other 86 that we have observed up here?

For temperature, this July was the second warmest that we have seen on record. The following table is the top 5 warmest summers we have seen as well as the 5 coldest on average. The average was made by adding the daily maximum and minimum and dividing by 2. The daily maximum and minimum are reported at midnight.

Top 5 Warmest July’s

Rank	Year	Average Temp.
1st	1955	53.5
2nd	2018	53.1
3rd	2013	53.1
4th	2006	52.8
5th	1952	52.6

Top 5 Coldest July’s

Rank	Year	Average Temp.
86^th	1962	44.3
85^th	1992	44.7
84^th	1956	44.8
83^rd	1954	44.9
82^nd	2000	45.1

One of the reasons that we saw such warm temperatures is because there was a large ridge that was centered over much of the eastern US. This allowed for warm, tropical air masses to flow into New England making it feel more like Florida in the valleys. The building can get uncomfortably hot during once the temperature starts to get into the 60’s and there is no wind. With all the State Park concession ovens going plus all the people up visiting can make for a warm stagnant air inside.

Now lets take a look at precipitation. We started off the month with a drought and much of the initial precipitation was from thunderstorms, which don’t always help in a drought. The reason is that rainfall rates are so high, much of the precipitation runs off into streams rather than replenishing ground water. The last few weeks of July saw much more in the way of frequent rain showers over multiple days which ended up helping relieve some of the drought here in New England but not all of it. We ended up with 9.11 inches of rain which was 0.34 inches above average which is 8.77 inches.

Wettest July’s

Rank	Year	Precipitation (in.)
1st	1996	16.85
2nd	1969	15.53
3rd	1997	15.46
4th	2009	12.99
5th	2008	12.88
22^nd	2018	9.11

Driest July’s

Rank	Year	Precipitation (in.)
86^th	1955	2.69
85^th	1948	3.28
84^th	2011	3.63
83^rd	1959	3.67
82^nd	1978	3.75

Finally we will look at winds! With the ridge over us for much of the month, the overall average wind was fairly low but with a thunderstorm early in the month along with a strong cold front after the heat wave, we hit 95 mph twice. Getting to 90 does not happen every July but having it happen twice or more has only occurred 14 times in our history. Here is a look at our windiest July’s and what place this year got.

Windiest July’s

Rank	Year	Wind Speed Avg.
1st	1983	32.8
2nd	1977	31.7
3rd	1935	30.5
4th	1997	29.9
5th	1971	29.8
52^nd	2018	24.5

So far this August has started off well above average again and looking into the first half of the month, it is looking like this trend will continue. The weather pattern is also conducive to frequent muggy days as well as continued showers and thunderstorms.

Adam Gill, Weather Observer/IT Specialist

A Hike to End All Hikes

2018-08-02 09:46:08.000 – Ben Seleb, Summit Intern

Despite living on the summit for most of the summer, my busy schedule has kept me from hiking Mount Washington from base to summit. With my internship at the Observatory coming to an end, and not having made the climb in its entirety, I made sure to find the time for it this previous weekend. Observer Adam Gill kindly joined me for the ceremonious occasion. Due to the threat of thunderstorms later in the afternoon, we decided on a shorter (but tough) loop up Ammonoosuc Ravine Trail and down Jewell Trail.

Our walk in the park was definitely not a walk in the park. Props to all the hikers that climb regularly! Except for the occasional break for water and to stretch sore leg muscles, our hike went without a hitch. Enjoy the following photos I took during the ascent.

A short break at the waterfall along Ammonoosuc Ravine Trail helped us prepare for the steep and slippery ascent that would be soon to follow.

This photogenic sign is located on most of the trails in the White Mountains, just above tree line. It wasn’t a big concern on the day we hiked!

We were mostly in the clouds before we made it to the summit, where we found blue skies and towering cumulus clouds that would be a sign of the storms which would arrive later in the day.

Try to find the critter that I spotted on our hike! He let me get close enough for a photo before Adam promptly scared him away.

I already mentioned that my internship is coming to end, and I’m not allowed to finish this blog post without getting a little soppy. As a mechanical engineering student, the Observatory was an unfamiliar field and a once in a lifetime opportunity, and contributed greatly to my knowledge and interest in the weather. I’d love to return at some point to experience the winter here. Until then, I’ll be thankful for all the experiences as well as the comradery that I shared with fellow shift members during our short time together.

Ben Seleb, Summit Intern

The never-ending Cloud

2018-08-01 16:16:43.000 – Simon Wachholz, Summit Intern

The last observer comment discussed why Mount Washington has such strong winds. This post, on the other hand, will discuss why we’re so often in the clouds. I’m sure many of you who have visited the summit in the past have had similar experiences: you’re at the base of the mountain and it’s a beautiful, sunny day, but then you get up to the summit and suddenly its cloudy with a visibility of 50 feet. Oftentimes it seems like the summits are the only cloud in the Northeast, so what’s going on?

Clouds generally form through one of three different processes: radiative cooling, mixing, or uplift. All three processes are relatively common, and in all of them water vapor in the air condenses to form cloud droplets.

A prime example of clouds forming through radiative cooling is morning fog. When the air cools overnight, the temperature decreases, but the amount of water vapor in the air remains constant. As the temperature falls, it becomes easier for the water vapor to condense into a cloud. That’s why in the valleys fog is common in the early morning and then dissipates once the sun heats the surface up again.

The second process occurs when two different air masses mix with each other to create a cloud. One air mass has to be warm and moist while another has to be cool and dry. An example of this cloud is when you exhale on a cold day and you can see your breath – the warm air in your lungs mixes with the cold air outside to create a cloud. Another manmade mixing cloud occurs when you’re boiling water in a pot. This cloud is often mistaken as steam, but steam is actually invisible so what you see are just liquid cloud droplets.

Getting back to why Mount Washington is so cloudy, the third type of cloud formation is from uplift, or rising air. When air rises, it cools the air to the point where the amount of water vapor in the air exceeds the saturation vapor pressure necessary for a cloud to form. Uplift occurs under several conditions. Perhaps one of the obvious ways to get rising air is when air flows up a mountain slope. Surprise, that’s what causes a lot of clouds to form around Mount Washington. This is the main reason why it can seem like a beautiful, sunny day in the valleys while the higher summits are immersed in clouds. A good example of this was on Monday morning when it was a sunny day in the valleys but Mount Washington was encased in a cap cloud with a thin lenticular cloud overhead.

Cap cloud over Mount Washington in the Morning

Webcam image from Wildcat looking towards Mount Washington Monday morning

Another type of uplift that isn’t topographically dependent occurs with thunderstorm formation. During the day, the sun heats the surface and the air near the surface. Since warm air is less dense than cool air, the air near the surface will become unstable and have a tendency to rise above the cooler air. If there’s enough vertical motion this can trigger clouds and eventually thunderstorm formation. Usually the summits are in the clouds when this happens so getting a decent view of cumulonimbus clouds isn’t possible. However, on Saturday conditions at the summit cleared while a thunderstorm passed to the Northwest.

Lightning in the Distance from the Summit of Mount Washington

Cloud to cloud lightning strikes in a thunderstorm off in the distance Saturday evening

So, if you visit the summit on a clear day consider yourself lucky enough to experience the incredible views of the White Mountains. Chances are though, you’ll visit on a cloudy day, but hopefully now you can appreciate being inside the cloud and why it never seems to dissipate.

Simon Wachholz, Summit Intern

World’s Worst Weather, Why?

2018-07-28 16:18:03.000 – Sarah Thunberg, Summit Intern

Mount Washington holds the title of “Home of the world’s worst weather” and holds the record for highest wind speed observed by man. At 6,288 ft. high, Mount Washington is not the tallest mountain in the world, it doesn’t even compare to many of the Rockies. So why does it have the worst weather in the world? Worst is a subjective term, it could mean high winds, heavy rain, lightning, or flying chunks of ice and debris. With regards to winds, Mount Washington has a clear leg above most other places on the surface of the Earth. The main reason behind the high winds is the shape of the surrounding mountains. Below is a map of elevation in the White Mountains from the US Geological Survey, Mount Washington is located at the black dot. When winds are coming from the west, the mountains create a funnel approximately 75 miles wide that converges on the Mount Washington.

Topographic map of Northern New Hampshire from the US Geological Survey

This funnel speeds up the winds the same way putting your thumb over the end of a hose speeds up the water flowing out. The elevation of the mountain compared to its surroundings also plays a role. The Adirondack Mountains in New York reach up to 5,000 ft. meaning there is 1,000 ft. of air that hasn’t been slowed down by any surface friction for miles hitting the summit at full speed. The nearest place that has an elevation of 6,000 ft. is the Black Hills in South Dakota, over 2,000 miles away. Mount Washington is the only place around for miles as high as it is, so there is no friction to slow down the winds, and it has a funnel to speed them up even more.

Storms also tend to pass over New England more than other areas in the US. The map above took 30 years’ worth of storms and tracked the path they took over the US. Most of these storms tracked over New England at some point. In the winter Mount Washington sees a new storm system every 3 days or so giving it lots of opportunities to see all ranges of extreme weather.

With respect to other categories of worst weather, Mount Washington still holds its own. Lightning? Yep, in most thunderstorms that come near the summit, the weather tower itself gets hit. Heavy rain? If you consider rain coming from every direction, up, down, sideways, while in the middle of the rain cloud heavy, then yes. Let’s not forget the flying chunks of ice. In most winter storms, the winds can easily get over 100 mph. If there’s any ice up on the summit, it’s not unreasonable to have large chunks of ice be blown off the buildings in those winds. Below is a picture of the ice buildup from one storm, now think if that building up storm after storm. Yeah, I would be scared to go outside as well, that’s why we have bulletproof windows.

So “Home of the world’s worst weather”? Yeah, I think so.

Sarah Thunberg, Summit Intern

Shift-Change Surprise

2018-07-26 18:06:54.000 – Griffin Mooers, Summit Intern

On our drive up to begin the new week’s shift, we came across something unexpected part of the way up the Mount Washington Auto Road. Though the summit of Mount Washington was socked in the clouds, in the mountains just below there was a gorgeous rainbow that had just formed. It was by far the most well defined double rainbow I’ve ever seen in my life. Our timing could not have been more perfect, as the rainbow faded only a few minutes after we stopped to admire it.

Rainbow over the Great Gulf during the morning shift change

Rainbow in the Mountains

Unfortunately, rainbows are a rare occurrence, especially on mountains. They require very specific conditions to be visible. Generally the sun must be behind the viewers, and low in the sky to get the proper angle. Any rain (or another form of water droplets such as sea-spray, mist, or a waterfall) must be in front of the viewer. When light strikes water droplets just the right way, they create the multicolored band we think of as rainbows.

Light going through a raindrop (NOAA.gov)

As light from the sun enters a water drop, it is refracted by the water. The light is then reflected off the back wall of the circular water drop. As it leaves the water droplet it is refracted a second time as soon as it hits the air again. This second refraction allows the light to separate into the colors we expect to see from a rainbow. When the angle of reflection is 42 degrees, we get the classic arc rainbow.

The Primary and Secondary Rainbows

If the light is reflected twice within the drop, a secondary rainbow can form above the primary rainbow. The rainbow yesterday was a classic example of a double rainbow. I’m looking forward to seeing more exciting weather like this in the weeks ahead.

Griffin Mooers, Summit Intern

Jasper, the Forgotten Cat

2018-07-23 15:31:32.000 – Emily Tunkel, Summer Intern

If you’re reading this blog post, you probably know about Mount Washington’s resident mascot, Marty the cat. Maybe if you really follow us closely (or you’re a little older), you know of Nin, a fat white cat who retired from MWO in 2008. And you’ve probably seen photos of Inga sitting outside in a storm, covered in rime ice.

But what about Jasper?

Recently, the other interns and I were tasked with combing through some of the old MWO news bulletins, all the way back to 1962. As I was looking through these hundreds of booklets, I found something interesting in the the winter ’82, summer ’82, and summer ’83 editions – mentions of a fat little orange tabby named Jasper.

The first reference of Jasper comes in the summer of ’82, where an article was written about Inga’s obsession will maiming and presenting live mice to the observers while she was in heat. Jasper was brought in to “[take] care of Inga’s ‘problem’”. The observers were hoping that Jasper and Inga would begin to “know” each other – biblically.

Jasper, however, had other plans. In summer of ’83, the MWO news bulletin stated that “Inga’s been in heat twice since Jasper’s come of age; still no cigar. How do you figure it?”

Apparently, Jasper wasn’t as romantic with Inga as he could have been, and ended up just being a weird cat overall. He stood on his hind legs to beg for treats (and dog bones), refused to use a litter box, was taught to lie down and roll over, and ate everything from dead mice to asparagus. In the summer ’82 edition of the bulletin, Jasper is nicknamed “garbage guts” due to his ability to eat anything at all. Greg Gordon, an observer at the time, wrote an article about Jasper entitled “Our Cat, The Dog”. I’ve included this article at the end of my blog.

While Inga went hunting for mice and ate dozens of flying squirrels (head first, leaving only the tails), Jasper was “not nearly clever enough” to catch them himself, and ended up eating whatever Inga would give him. He hated children, but would let adults pick him up and carry him around – only upside-down, however, on his back. After Inga passed away in 1994, the observatory welcomed Nin, who Jasper was not fond of (mainly because Nin would steal his food). Jasper lived for fourteen years at the observatory, and passed away in 1999.

“Our Cat, The Dog” – Greg Gordon

Jasper (what we formally supposed to be a tomcat), never has hit it off very well with Inga. Initially, we figured it was simply a question of a territory violation, but increasingly, this hypothesis has become suspect: for one thing, Inga has never had any trouble getting along with Pushka – TV’s feline; not only have there been no territorial disputes between them, but we frequently have to drag Inga back over here – especially when she’s in heat (she is not in the least discouraged by Pushka’s sexual neutrality, a situation we hoped Jasper’s presence would remedy). But there are other grounds for suspicion: in many ways, Jasper doesn’t act like a cat at all: he lacks a cat’s agility and coordination – he honestly can’t get out of his own way. He loves to play in the water (something no self-respecting cat would have any part of), and we’ve had the darndest time getting him to use the catbox! Those of you who are cat owners have probably noticed that cats don’t usually shift their eyes when altering their focus of attention; more often than not, they turn their heads. Not Jaspy, and here’s another thing: Inga’s been in heat twice since Jasper’s come of age; still no cigar. How do you figure it?

And there’s more: when Jasper wants something to eat (which is most of the time), he stands up on his hind legs, and begs – just like a dog…Not only that, but he eats like a dog – just wolfs everything down without bothering to chew it first. He has been known to pant, and wag his tail; he even likes bones! And as if all that weren’t enough, he actually lies down and rolls over!

We inquired of John, who brought him up here, whether Jasper had had an unusual upbringing – possibly some traumatic experience early in life which would account for his strange behavior!

“Nope,” John assured us. “Perfectly normal.”

Maybe some of you down there in the real world can shed some light on this. Woof, woof?

Emily Tunkel, Summer Intern

Seek the Peak 2018!!

2018-07-22 11:32:14.000 – Ian Bailey, Weather Observer/Education Specialist

Time for another blog post! Our Seek the Peak event was amazing! Over the last several years during the event, the weather has been, well, questionable. High winds, foggy views, and even precipitation played into what some have called a “more rough than anticipated” hiking experience. But not this year. Not at all. We had a very strong high pressure settled in over the region, with plenty of dry air and light winds to help set up a clear, blue, beautiful day for Seek the Peak.

We had several days of this beautiful weather leading up to the event. Of course, it’s not the ripping 95 mph winds from last shift. But I’d rather it be clear and sunny for the hikers. We did get a bit of excitement on Seek the Peak Eve though! A cap cloud settled in over the summit. But given the dry air mass, it wasn’t enough to sock us completely in the fog. Rather, it gave us some opportunities for some incredible pictures!

What had us running outside initially was this lovely atmospheric optical phenomenon known as Brocken Sprectre. Or, as the Observers like to yell, “ZE BROCKEN SPECTRE!”. This is definitely a right place, right time phenomenon to observe, as it requires the observers shadow to be centered amidst a “Glory”, or concentric, rainbow-like rings that form opposite the sun as the light bends through the billions of tiny water droplets in a cloud/fog. So when we climbed on to the parapet of the tower to check out the cloud, we saw the glory behind us and immediately began snapping. Additionally, with the cap being as light as it was, we could get some cool sun pictures too!

So after a good night’s rest, our crew and the incredible team of volunteers woke up and prepared the Obs for tours! We had previous observers, previous interns, members, trustees, and so many other wonderful individuals to help us with the tours. And it made for a really fun and interesting event! I got to watch and listen to people who worked here previously share their stories and perspectives on the Obs, living on the summit, and some of the storms they have seen in their time up here. And I learned a lot! And along with that, I got to talk to many people who hiked up, what they thought of the trails, the Mountain, and some of my experiences up here as well. It really was a fantastic time!

At one point in the day, we stopped tours to allow for the unveiling of the brand new plaque in our Weather Room! Jack Middleton has been a member of the Observatory for a very long time, and has been donating an immeasurable amount of his time and passion to the work we do up here! As an Observer in 1952 and 1953, he has many incredible stories and experiences to share. And it was wonderful to get the chance to speak with him and share stories. In honor of all that he has done for the Observatory, we had an unveiling ceremony of his plaque, and christened our headquarters as the Jack B. Middleton Weather Room! He had many of his friends and family in attendance, and it was a wonderful moment to share with my fellow crew members.

We resumed tours after the ceremony, and by the day’s end we had given 145 tours! The hikers were so excited to have a chance to come in, ask us questions and, of course, go to the top of the tower! And it was great to be a part of their experience throughout the day! But by mid-afternoon, it was time to depart the summit and head down to the base for the hiker expo and the famous Seek the Peak turkey dinner! Adam heroically volunteered to stay behind to continue the observations, giving the rest of our crew the chance to enjoy the festivities. And we are very thankful he stepped up for us!

The hiker expo was a lot of fun too! There were great prizes given away, massages being given to the hikers in need, music, corn hole and, my personal favorite, GIANT JENGA!

Myself, Ben, and volunteer Mike played several rounds of the anxiety inducing game, with each of us winning at least once! So that was a blast! And our crew even got the chance to win some prizes at the Eastern Mountain Sports booth! They had trivia questions that they tried to stump us with. But intern Zach came in clutch, nailing his trivia question where they asked him to name each of the Presidential Peaks from South to North! He even remembered to skip clay, since it’s not technically a peak. So he nailed it, and it was fun to watch!

And of course, the dinner was amazing too! Turkey, mashed potatoes, stuffing, and rolls. Everything a tired, hungry hiker could ask for! So while we ate our delicious meal, Sharon and the other organizers gave out awards to hikers (the Kilted Hikers are the Kings of the Castle once again this year! Congrats you guys!!!) and raffled off prizes! It was nice to see so many people who care about the Obs so much! And to see who was responsible for raising so much money for our cause was really nice too! It really put things into perspective for me coming back to the Obs.

It was also a great opportunity for us to talk and relax with the other crew! Normally we only get to talk and “socialize” during shift change. And those times can be busy and stressful. So it was wonderful for us to be able to sit down together, eat, relax, and tell stories and jokes with each other. You have to seize moments like that when you can, because they don’t come around terribly often with the way our schedules are structured. So I really enjoyed that opportunity as well.

All and all, it was a fantastic Seek the Peak. The weather was beautiful, the hikers were friendly and gracious, and the festival at the base was a ton of fun! And as we returned to the summit after dinner to resume our duties, we were welcomed by yet another glorious sunset.

I’m so glad that I am back here and once again a part of this amazing Mount Washington Observatory community. It warms my heart to know that so many people care about this place as much as I do, maybe even more! And as the sun set on our wonderful event, I went back to work feeling refreshed, inspired and excited, fueled by the smiling faces and happy stories of all of the wonderful people I had met and talked with this weekend.

Thank you all so much to everyone who participated, donated, and came out to Seek the Peak. Every dollar raised helps the Obs in a huge way, and I speak for everyone up here when I express how truly grateful we are to you all! I am very much looking forward to another fantastic Seek the Peak next year!!!

Ian Bailey, Weather Observer/Education Specialist

One Cloud to Cover Them All

2018-07-17 07:11:23.000 – Sarah Thunberg, Summit Intern

Every meteorologist has a favorite cloud type, for most people this has something to do with severe weather. I get it, supercells are really cool and exciting and give conditions where you can see really unique clouds like pileus or mammatus. These clouds are too rare and energetic for me. Give me a nice stratus deck any day and I’ll be happy, better yet, layered decks. There’s just something so comforting and peaceful about a smooth ocean of white. A stratus day is a good day. If I’m on the mountain I can watch the deck slowly drift over and around the peaks and change shape as it flows. Off the mountain I can sit at home and read a book or watch the rain fall on the windows and leaves. Either way, I can easily clear my mind and unwind.

I took the picture above back in June after the summit cleared out of the clouds from rain overnight. This stratocumulus deck was so detailed and had beautiful smooth streaks imbedded in the deck.

This sunset was one of the prettiest I’ve seen up here on the summit. The sky wasn’t terribly red, but there was such a pretty deck off to the east and the haze made the mountains various shades of indigo. It was framed to beautifully.

I took the two images above this week on Saturday morning before the summit went into the clouds. The first one shows the eastern expanse of a stratus deck to the south spilling over Wildcat. The second image was taken to the west showing the same deck looking out over the southern Presidentials.

Sarah Thunberg, Summit Intern

Where is the Wind this Week?

2018-07-15 18:09:32.000 – Griffin Mooers, Summit Intern

The Mount Washington Observatory’s claim to fame has long centered on wind, with the observatory seeing the highest wind gust ever (recorded by man) at 231 mph on April 12th, 1934. And at an average annual wind speed of 35 mph, the observatory has the highest average wind of any station in North America. And it’s personally given me by far the strongest wind’s I’ve experience in my life, with gust’s over 90 miles an hour on previous shifts. But so far this shift, the mountain has not lived up to its reputation as the home of the world’s worst weather.

Average daily wind speed for the shift so far according to the RMYoung Wind Speed and Vane Instrument

Although these winds may not be the ‘extreme’ that people expect from Mount Washington, in truth, it’s not unprecedented at all. On Mount Washington, the northeast, and the northern hemisphere more broadly, winds tend to drop off in summer as compared to winter.

Mount Washington’s average monthly wind speeds in mph (mountwashington.org)

The summer the wind speed average, in miles per hour, hovers in the twenties, which is well below the average of 40s in the winter months. This substantial difference is largely due to a changing temperature gradient.

Image from the North Carolina Climate Office showing seasonal movement of the polar jet

The temperature gradient between the equator and the poles decreases significantly from winter to summer. This in turn causes the polar jet, which is located far to our south in the winter (Generally around 40° N) to weaken substantially and retreat far up into Canada.

Jet Stream separates cold and warm air masses (nasa.gov)

The polar jet stream normally acts to separate the cold air mass from the warm air mass. But as it weakens and moves north, the division between cold and warm, as well as between high and low pressures, decrease. Wind is simply the flow of air away from a high pressure or towards a low pressure. When the gradient of the pressure decreases, the speed air flows also decreases. So although our summers are still windy compared to other locations in the region, the weakening summer hemispheric temperature gradient makes them more mild, especially compared to the mountains winter’s, when the wind frequently gusts over 100 mph. These calmer conditions make summer an ideal time to come up to the summit for a hike or visit.

This is not to say that extreme winds never happen on Mount Washington in the summer. All visitors should always be prepared for harsh weather, even in summer. An example of strong summer winds was July 20, 1996, when the wind gusted up to 154 mph. However, these powerful winds normally need a powerful external trigger in the summer, such as a tropical system moving north into New England, or a line of powerful thunderstorms passing through the White Mountains.