Brutal Cold on Mount Washington: A Weather Story

Hello! My name is Karl Philippoff and I am a new weather observer at Mount Washington Observatory. Although I am from New Jersey, I have been up on the summit multiple times – once as a tourist, once as a thru-hiker, once as a summit volunteer, and most recently as an intern.

I am very excited to experience all that a winter on Mount Washington has to offer. I also feel incredibly lucky to have one of the most beautiful views I can imagine from my desk, looking out at the Northern Presidentials.

In my brief time on the summit, I have already experienced a slew of firsts, including using a mallet as part of a job (to de-ice the wind instruments), being encased in rime ice while de-icing said instruments, experiencing wind gusts over 100mph, commuting to work via snow tractor, and being an active part in one of the biggest weather stories in America on Feb. 3 and 4.

Here I am, holding the mallet we use for de-icing the wind instruments

I have been fascinated with the weather since I was young, with some of my formative weather experiences including waking up the morning after the Blizzard of ‘96 with snow drifting nearly over my dad’s car (which he had parked out near the edge of the driveway in the hopes of getting to work that day. He did not.) and watching then-tropical storm Floyd completely transform the lake in which I enjoyed swimming into a wave pool that flowed over the dam and created a raging torrent of water. Experiencing weather at its worst has always fascinated me, and was certainly part of what made me want to work at the Home of the World’s Worst Weather.

I studied environmental science with a focus on meteorology as an undergraduate at the University of Virginia before studying tropical ice core records for my master’s research at The Ohio State University. I eventually decided to do a bit of U-turn and return to get a bachelor’s in meteorology from Rutgers.

My other principal passion is being in the mountains. I love their uniqueness and the awe and wonder the peaks inspire. I love the physical effort required to experience them and the sense of accomplishment you feel afterwards, a ‘mountain high’ if you will. They require you to push yourself, but the views at the end make it all worth it (usually). This passion was the main reason I thru-hiked the Appalachian Trail over the course of four months last summer into the fall. I have had the distinct privilege of hiking and viewing many different mountain ranges, but until I ventured up Mount Washington on Jan. 4 this year, I had never lived at the summit of a mountain for any length of time.

But enough about me. Let’s take a closer look at what transpired on what was a truly memorable and historic extreme week at the summit for Weather Observers Alexis George, Francis Tarasiewicz, and myself, our two summit volunteers Pat Luddy and Steve Moore, and Mount Washington State Park employees Christopher Lavigne and Nate Camille.

Francis and I were looking at weather models last shift and it was apparent we might get some very cold weather on the summit during the first weekend of February. This was after January had been snowy but the warmest on record for the summit, with only three days below normal, and a monthly average temperature of 10.3 °F above normal. However, weather models that far into the future are not always accurate, and I did not think much of it. Boy was I wrong.

By the time of our shift change meeting on Wednesday, Feb. 1, the predicted cold was well within the time frame that model forecasts are fairly accurate, and we were predicting winds over hurricane-force to coincide with potentially record-breaking cold temperatures, producing nearly unfathomably cold wind chills.

This was also when I was told that it was likely that I would need to assist our night observer, Alexis, during the coldest time period Friday night, possibly into early Saturday morning, in anticipation of breaking not only the all-time Mount Washington Observatory station record of -47 °F set on January 29, 1934, but possibly surpassing the coldest temperature ever observed in New Hampshire in modern history, the -50 °F observed on January 22, 1885 by the Army Signal Corps on Mount Washington. (And yes, our station record is not -50 °F because of the nuances involved in instrument siting and the lack of continuity between when the Signal Corps stopped recording weather information in the 1890s and when Mount Washington Observatory was established in 1932.)

I knew already that if we were to get near that cold, I would probably not be sleeping through Friday night anyway, but would be refreshing the current conditions page on my phone through the night. All-time records at stations which have existed for 90+ years are hard to come by, and I was ready for it.

There was also the possibility that a tropopause fold could move directly over Mount Washington. This was important because the tropopause is an inversion above which temperatures are typically steady or increase with altitude. Such layers are what meteorologists term “stable,” meaning they resist vertical motions and can act as a lid over the atmosphere below. Having this layer come down to summit level could accelerate the anticipated hurricane-force winds even further, similar to how when you put your thumb on a garden hose, the portion of the water stream which is not blocked by your thumb is accelerated substantially compared to its unimpeded flow. In this analogy, the ‘thumb’ was a combination of the strength of the inversion layer and the sheer height of Mount Washington serving as an obstacle to the onrushing arctic air, and the ‘water’ was some of the coldest deep-level air in the world at the time, and that I had ever seen.

In addition, since the summit was supposed to be above the tropopause boundary, we might be expected to smell ozone – which has a pungent odor similar to chlorine bleach – during our observations, as ozone, usually firmly ensconced in the stratosphere, could be paying us a visit all the way down at 6,288 feet above sea level.

A brutally cold air mass arrives at Mount Washington on Feb. 3. Watch this video showing high winds and flying rime ice blow past the Sherman Adams Building.

This was all leading up to a memorable Higher Summits Forecast that I issued on Wednesday afternoon, where I had to explicitly caution outdoor recreationists about the increased risks for hypothermia and frostbite, and that camp stoves may not work because the fuel used to power them may gel or freeze solid in such cold conditions. I forecasted temperatures to slide to 40 degrees below zero by Friday afternoon on the summit, with winds increasing to well above hurricane force, producing wind chills of nearly 100 degrees below zero. Let me say that again. 100. Degrees. Below. Zero. In other words, it would feel colder than any temperature ever measured outside of Antarctica in the dead of winter. Yes, yes, wind chills are apparent or ‘feels-like’ temperatures, but it would not change the fact that we were about to experience “wicked cold” conditions in the words of one reporter who talked with Francis on Thursday. And it was all going to happen in my third week at the summit.

The weather fanboy in me was certainly getting excited by Thursday when the area forecast discussion for Gray, ME blared out “***ONCE IN A GENERATION COLD WIND CHILLS POSSIBLE FRIDAY NIGHT INTO SATURDAY***.” I had memorized notable weather statistics since elementary school, but this was the first time that I would be responsible for actually measuring them.

The model output statistics for the two models we use as guidance for issuing our Higher Summits Forecasts were calling for temperatures down to -50 °F, well under our station record. The first indications that Mount Washington would soon be front-page news started on Thursday with Francis fielding interview requests from The Boston Globe, CBS, CNN, NPR, and Reuters, sometimes even having the phone ringing in another room while he was already on a call.

Our Director of Weather Operations Jay Broccolo had been called to a press conference with the governor of New Hampshire, Chris Sununu, to caution the public about the weather conditions expected in the mountains Friday into Saturday. This, of course, in a state whose famous motto is “Live Free or Die.”

This reached a head for me, personally, when browsing on my phone before going to bed Thursday night, I saw an article in The New York Times mention our -100 °F wind chill forecast for Friday night. I tried and was ultimately successful in getting some sleep Thursday night before getting up bright and early at 2:30 a.m. Friday to assist Alexis when the weather started to deteriorate. It would be quite the memorable next day and a half for us at the summit.

Mind you, I did not think that I was volunteering for a well-over 24-hour shift, which started when I woke up on Friday. According to most models we had been looking at, the window during which we would experience the absolute minimum temperature was supposed to be fairly narrow between about 10:00 p.m. and 1:00 a.m. Friday night into early Saturday morning. Instead, we dropped to -45 °F by the 6:00 p.m. observation on Friday, and did not rise above -45 °F until the 7:00 a.m. observation on Saturday morning, 13 hours later.


Alexis’ Note as the Night Observer: While at least one observer and an intern work during the day at Mount Washington Observatory, the night observer typically works alone. The night observer may wake up another observer or intern when extra help is needed, but the night shift workload can commonly be handled by just one person. With the potential for temperatures to break record lows overnight Friday, it would be necessary to measure temperature with the sling psychrometer more often to record the absolute minimum temperature. I was told at shift change on Feb. 1 that if I needed help with slinging overnight Friday, to wake up Karl. I had no expectation that Karl would have to stay up the entire night on Feb. 3. Due to the extreme cold and windy conditions that we were forecasting at Mount Washington overnight, it was determined Thursday that it would be unsafe for just one observer to work alone Friday night into Saturday morning. Another person would need to be awake for safety reasons, and to assist the night observer when more frequent measurements would be needed. It was initially discussed that Francis would stay up for the first half of the night on Feb. 3, and Karl would take the other half. However, since Francis had been getting so many interview requests for Friday, it was decided that he did not need the added burden of staying up on top of all of his other duties as the only other trained observer on our shift. As a result, Karl got up at 2:30 a.m. on Friday and stayed up until 9:30 a.m. on Saturday during the worst of conditions, a whopping 31-hour shift.

We started slinging every 30 minutes around 9:00 p.m. as temperatures had already dropped to the February monthly record low of -46 °F. Tasked with a long night ahead, I was glad Karl was up to help out. It was not necessary for both of us to go out in those extreme conditions. As long as one person was inside the weather room, they could keep an eye on the outside observer using the deck camera, as well as notice if they had been outside for an abnormally long time. But Karl was eager to go outside to experience the extreme weather and I found his enthusiasm and excitement contagious as the long night stretched towards morning. Every time Karl suited up to go outside, he would clap his mittens together twice in quick succession, either to ready himself to venture out into the most brutal of weather conditions, or just psych himself up for yet another observation. I found this to be hilarious and told him so towards the end of the night. It had seemed like temperatures had leveled out between 10:00 p.m. and midnight, until there was another drop in temperatures around 12:15 a.m., which led us to start taking temperature readings every 15-20 minutes until 5:15 a.m. It was also right around this time, when we needed to sling more, that I was tasked with an extra-large workload. As the observer on duty, I needed to make sure that the synoptic observation was filled out correctly, that the broken records were reported correctly on all Observatory forms, and to emphasize in the morning Higher Summits Forecast discussion that the dangerous weather conditions would linger through Saturday. I was glad for Karl’s help as he slung more in between hourly observations in case we dipped any lower than the all-time record low.


Since we were so close to the all-time record low for much of this time, beginning around 10:00 p.m. on Friday, we began taking measurements every half-hour, and by 12:15 a.m., we started to take them every 15-20 minutes until 5:15 a.m., ultimately totaling 22 measurements during these seven hours. This entailed basically non-stop work with very little downtime since it took about 3-4 minutes to get dressed to go out in the extreme conditions, about 4-5 minutes to take the observation, and then about 1-2 minutes to remove gear and breathe before attempting to do it all again.

Why would I remove gear? Because sweating underneath all those clothes, especially going outside as frequently as I did, would have been a recipe for disaster. And on top of that, it was very hard to move my head freely and breathe with a facemask, sweatshirt hood, hat, puffy hood, shell hood, goggles, and a headlight (for the night shift) all on at the same time.

I was so muffled up that when I returned to the weather room to give Alexis the temperature readings, I had to make her wait in suspense while I freed my voice from underneath all the layers.

Towards morning, during the brief interludes between gearing up, removing gear, and taking measurements, I looked at the temperatures at some of the stations upwind of Mount Washington to the north and west and noticed that after similarly long periods of stasis, their temperatures had started dropping ever so slightly by early Saturday morning. Shortly thereafter, the Foxboro digital thermometer — located on the observation deck — and our sling psychrometer measurements also seemed to show a small, but at this point record-tying dip. After having held steady between -45 °F to -46 °F for six hours, we were consistently getting measurements below -46 °F. At 3:40 a.m., we measured a -46.6 °F reading, and the Foxboro was indicating that temperatures were still dropping. I slung again at 4:10 a.m., and Alexis came out to assist me in reading while I slung. I stepped out from the sheltered location in the lee of the tower into the brute force of the 90+ mph winds to get the best exposure to the coldest air flow. One of the reasons that I had asked Alexis to assist me in reading the thermometer was that, due to how I was bundled up against the cold, my breath would become trapped within my layers and freeze on the inside of my goggles, making it near impossible to read the temperature through them. In order to read the thermometer accurately, I had had to take my goggles off in the lee of the building. In this instance, I dashed over to Alexis so she could read the alcohol at its lowest point and confirm my previous reading. It read -46.7 °F!

We had done it! We had tied the all-time record low temperature at Mount Washington Observatory, equaling a record that had been set 89 years ago.

Our B-16 daily weather form, with our station’s record low being matched around 4:00 a.m. on Feb. 4.

I think I can anticipate some of the questions that will typically be asked about weather conditions like this:

What did the weather conditions feel like?

Properly suited up underneath six layers on the top, three layers on the bottom, incredibly thick boots, and a combination of three hoods, a balaclava, a hat, a neck gaiter, and goggles, it was not all that bad. You immediately noticed any exposed skin, which felt most like a pretty severe sunburn. Even unexposed skin that was near creases or cracks of clothing felt like a low-degree burn, which for me was the gap between the top of my goggles and all of my hoods. As long as you were only out for a few minutes at a time in the lee of the tower it was almost comfortable. With more exposure to the wind, however, it cut right through to my legs, like they had been dunked in cold water, especially when I went out for two short stints on the parapet. Holding anything metallic, like a phone (more on this in a bit) or the sling psychrometer, almost immediately made those fingers cold, with a slight numbness noticeable after a few minutes. On top of the cold was of course the wind, which as soon as you stepped out onto the observation deck sounded like the constant roar of jet engines at some remove on a plane that refused to take off.

How did we take observations in such conditions?

For the most part, we let nature do the work, especially during the worst of the conditions. Since we were experiencing such cold temperatures with considerable winds, we mostly sheltered ourselves behind a windscreen in the lee of the tower while sticking one arm holding the sling psychrometer (for non-meteorologists: a thermometer) through the windscreen slats into the wind. Since the summit was in the fog for most of the arctic blast, we were most interested in the dry bulb reading, especially for the sub-hourly observations Friday night into Saturday morning. After holding it steady for a few minutes in order for the temperature to stabilize to near the ambient air temperature, we would quickly read it at its lowest point, or move several yards downwind of the tower, sling for 20-30 additional seconds, and read it then. Later on, thinking that we had been too close to the building, I went to a slightly more exposed location for about 30 seconds before dashing back into the lee of the building to take measurements as quickly as possible, as it was impossible to hold the thermometer still enough to take measurements in the blustery winds. Quick measurements were necessary because the temperature would often rise a few tenths of a degree the longer we held the thermometer steady in the lee of the building, presumably due to the combination of the building, mittened hands, and faces all becoming significant heat sources at such low temperatures.

What did I wear?

The short answer is everything. The long answer is my moon boots, so-named because they lift me about two inches off the ground and look like something an astronaut would wear on the moon, and heavy wool socks on my feet. A very heavy and a lighter pair of long johns and insulated snow pants on the bottom. And a skin-tight polyester layer, a medium weight wool top, one medium weight fleece with a hood, one heavy weight fleece, a down jacket and a shell jacket on top, with a balaclava, hat, neck gaiter, and goggles to top it off. I got pretty good at dressing and undressing quickly as the day wore on.

Were we scared/frightened/terrified?

There was only one time that I think Francis and I were concerned for our safety and that occurred Friday afternoon during what turned out to be the highest wind gust we experienced during the event. While heading out for one of our hourly observations, the door to the observation deck slammed shut without warning, hitting Francis in his heel. It took us about 20-30 seconds to pry the door open again. As this happened, we both think the latch on the door to the catwalk (at lower portion of the tower) broke in half, which we noticed heading down the stairs from the observation deck. Francis, initially on his own, then with help from me and one of the volunteers, managed to pin the door mostly shut while Francis found a Mount Washington State Park employee, who managed to install a new latch, and later, a 2”x4’’ to ensure the door would not open again. Needing to limbo under and over this new obstacle, which was at about waist height for me, made subsequent observations even more of an adventure.

The only other time that I was more than a little concerned was when I fell down briefly in the more exposed location, while slinging, just before taking a measurement. Due to how the westerly to northwesterly winds flow around the structures on the summit, I was temporarily caught in the worst of it for a short time as I could not stand up without fear of being blown further down the deck. I managed to get myself back to where I had been standing previously by sitting on my butt and inching myself backwards, taking advantage of the slower winds near ground level. 45 seconds later, I was back to slinging again.

Any other memorable moments?

I have a few more memorable moments. As we got closer to our all-time record low, we thought it would be a good idea to obtain some photographic evidence of our lowest measured temperature. We did go to some lengths to get this information, but we were not entirely successful. In such cold weather, working a camera using glove liners was not going to be possible, but after some trial and error, we thought using the video function might work. By hitting the record button before going outside, it would be possible to take a still out of the footage for record-setting purposes. The problem was that at night, it was very hard to shoot the thermometers without glare and keep it steady with mittened hands in strong winds. This combined with the fact that holding the thermometer steady for too long caused the temperature to start to rise, and made it nearly impossible to collect the required footage. We ultimately decided it was more important to make the necessary measurements by eye than record each of them with a phone. On a related note, I have to say I was very impressed by my phone’s ability to function in such temperatures and not die after freezing and thawing multiple times throughout the event. I can only hope that it remains working for a long time to come.

Our windows in the weather room were not the most weather-tight, with frost forming on the inside of the window jambs right next to the heaters. We usually use the heaters next to the windows to heat up and dry out our outerwear after each observation, but the extreme cold made this less useful. Instead, we had to pile our clothes on the table several feet away from the windows to at least keep them near room temperature. One of the volunteers had left a glass of water on top of the heater in the corner of the room Friday night, and by Saturday morning, it had frozen solid.

The extreme temperatures also made the building creak, sounding like muffled gunshots as the steel and concrete contracted at different rates in the extremely cold temperatures. This, on top of the fact that the heater near my desk startles me nearly every time it turns on, kept me on edge for most of Friday evening and Saturday morning.

The constant winds sustained near 90-100 mph for most of the event whistled around the building. As the winds turned slightly more northwesterly Saturday, they sounded like a high pitch shrieking through the door that opens from the outside to the weather room. This prompted one reporter to ask Francis whether he could turn that sound off, to which Francis replied that it would be hard to turn off the wind. Shoving some folded-up paper into the slits around the door did help to reduce the whistling somewhat and kept us slightly more sane.

Some statistics from the event:

  • Temperatures at or below -45 °F for 13 straight hours
  • The -47 °F reading (rounded) is the coldest in 89 years, tying our record low. Our lowest recorded slung temperature of -46.7 °F may be the lowest temperature ever measured in Mount Washington Observatory records, to the tenth of a degree, as the lowest temperature slung by the weather observers in January 1934 was -46.5 °F as reported in their journals and a brief article published in the Monthly Weather Review in February 1934.
  • Wind chills below -100 °F for 15.5 straight hours
  • -109 °F was the lowest wind chill noted on our current conditions page, on at least three occasions
  • Sustained winds greater than 82 mph for 28 straight hours, with a top gust of 127 mph
  • Zero hours of sleep while recording all of this extreme weather

Our Current Summit Conditions page shows a -109°F wind chill on Feb. 3 at 11:35 p.m.

I would like to thank all the people who were at the summit during this cold wave. The two volunteers, Pat and Steve, kept us sane under insane conditions and calmed us down when things were getting intense. We greatly appreciated your joviality and cooking(!) under trying circumstances. To the Mount Washington State Park employees, Chris and Nate, you guys kept the building and Curly, Larry, and Moe (our heaters) running smoothly throughout the event and allowed us to concentrate on the weather observations. You also stepped up when the door blew in and kept the weather we were observing outside the building. And to Francis and Alexis, I would like to thank you for your friendship, tenacity, and professionalism throughout the event. We were tested, but were not found wanting.

Alexis George, Francis Tarasiewicz, & Karl Philippoff withstood & recorded extreme conditions at our summit weather station on Feb. 3-4.

Karl Philippoff, Weather Observer – Research and IT

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