Behind the history of Mount Washington's fabled 231-mph wind gust

·7 min read

Home to extreme subzero cold, thick fog and blizzard conditions, the highest mountain in the northeastern United States -- Mount Washington in New Hampshire -- is rather infamous for its erratic and ferocious weather.

And nearly 100 years ago, the full force of that fury was unleashed into a heightened state, generating record wind gusts at the summit.

Wind and driving snow are seen on the top of the highest peak in the Northeast, Mount Washington, in New Hampshire. (AP Photo/Jim Cole, File)

On April 10, 1934, staff at Mount Washington Observatory woke up to a cold but typical April day. A high of 36 degrees Fahrenheit was observed for the day with a low of 29 degrees.

Two storm systems were situated over the eastern part of the United States -- and both were heading toward Mount Washington and New England. One of the storm systems was located over the western Great Lakes and was tracking to the east, while another batch of energy was situated off the coast of North Carolina. Adding greater intensity, a large ridge of high pressure sat over eastern Canada and the northern Atlantic.

As the setup began to brew across the continent, the weather remained calm and quiet in New Hampshire. "April 10. A perfect day. Cloudless and calm. Hazy. Sun dogs at 5:30 p - a refraction phenomenon of no special importance," Mount Washington Observatory staff member Salvatore Pagliuca wrote in his logbook on April 11, 1934.

The Mount Washington Auto Road Stage Office, where the Observatory was first established, with an anemometer mounted on the roof and thermometer housing mounted on the northern exterior wall. (Mount Washington Observatory/

For the next 24 hours, high pressure continued to build, creating a blocking pattern over the Atlantic, which forced the energy from North Carolina to move to the northwest and combine with the storm in the Great Lakes. But at Mount Washington, conditions still remained mostly calm.

April 11 soon arrived as another quiet and clear day for Mount Washington, but the clear skies would become increasingly overrun by clouds by afternoon. Into the evening, fog was observed at the summit and obscured the mountain, quickly making the beautiful weather a distant memory. Thick ice began to form, with 1-foot-thick rime ice reported.

High pressure continued to build to the north and east of New Hampshire, with the low pressure gaining strength to the west. This resulted in an abnormally tight pressure gradient forming to the north and east of the storm system. The tighter the pressure gradient, the quicker air rushes from high to low pressure, resulting in higher winds.

Winds on the summit continued to strengthen into the night, reaching as high as 136 mph. That night, observatory staff member Wendell Stephenson volunteered to monitor conditions during the overnight hours. Pagliuca wrote in his logbook that the increasing wind was "to values never dreamed before."

The pressure gradient between the storm over the eastern Great Lakes and the Carolinas had grown extremely tight on the northeastern portion of the low pressure, creating abnormally strong southeast winds for Mount Washington. The pressure gradient is the difference in pressure between high and low pressure. When the pressure gradient strengthens and becomes tighter, wind speed increases.

Alex McKenzie (left) and Sal Pagliuca tighten the guy wires holding the anemometer to the roof. (Mount Washington Observatory/

Stephenson woke up at 4 a.m. on April 12 after taking a short nap, noticing the strong winds sounded louder than before. He checked the anemometer and began to convert the reading to the true value. Stephenson found the average wind speed was 105 mph. Due to ice buildup, the instrument used to record wind was hampered and showed a lower value than Stephenson expected.

The winds were so strong that when Stephenson went to suit up and grab a wooden club to clear the ice, the pressure knocked him to the floor when he went to open the door. Stephenson had to then climb a ladder in the heavy winds to rid the instrument of the ice buildup.

"When winds start hitting 100 mph or greater, it's very difficult, not only to be able to stand, you can hardly even move and if you fall down, it's very difficult to get back up," Patrick Hummel, the park manager for Mount Washington State Park, told AccuWeather's Lincoln Riddle.

Luckily, the wind was to Stephenson's back, which helped him maintain his footing as he climbed the ladder. Stephenson was able to successfully clear the ice from the anemometer after dozens of blows with the club.

After clearing the ice, he went back inside to get a corrected wind speed measurement. After three tries, Stephenson had verified winds topping 150 mph. A continuous reading of the instrument would soon follow as the rarity of the storm became clear.


"I dropped all other activities and concentrated on observations. Everyone in the house was ‘mobilized' as during a war attack and assigned a job. The instruments were watched continuously so that they may give a continuous and accurate record of the various meteorological elements at work. The anemometer was particularly watched," Pagliuca wrote in his logbook.

The anemometer used by Stephenson was heated and designed specifically for Mount Washington. The instrument was tested in a wind tunnel at the Guggenheim Aeronautical Laboratory of the Massachusetts Institute of Technology.

As morning turned to afternoon, the winds strengthened further and soon approached record territory. Winds of 220 mph were recorded just after 12 p.m., with some gusts even reaching 229 mph. At 1:21 p.m. that day, the highest reading of the day occurred.

"'Will they believe it?' was our first thought. I felt then the full responsibility of that startling measurement. Was my timing correct? Was the method OK? Was the calibration curve right? Was the stopwatch accurate?" wrote Pagliuca.

An astounding, 231-mph wind gust out of the southeast was recorded by the observation staff, becoming the highest natural surface wind velocity ever recorded from an anemometer, according to Mount Washington Observatory.

Observer Aubrey Hustead holding the No. 2 heated anemometer that recorded the 231-mph world record wind. (Mount Washington Observatory/

The strong winds would last into the evening, not letting up until the storm moved north and began to weaken. By the next day, it was already over, and high temperatures rose into the 50s for the next couple of days.

The National Weather Bureau, which preceded the National Weather Service, ran a number of tests on the anemometer that recorded the 231-mph wind gust, eventually verifying the reading.

The observatory conducts wind research for a number of reasons, including to better understand how climate and the atmosphere affect ecosystems in the area as well as for commercial purposes. The observatory partners with some businesses to conduct tests on consumer goods ranging from windows to skincare products.

This high wind record would remain for over 60 years, eventually exceeded by a 253-mph wind gust that was reported in Barrow Island, Australia, during Tropical Cyclone Olivia in 1996. That measurement set a record that still stands today for the fastest wind speed ever recorded on the planet.

However, both the Australia reading and a 302-mph wind gust measured by Doppler radar in a tornado in 1996 were done by remote instruments, leaving the reading from Mount Washington as the highest surface wind speed ever observed by a human to this day. Excluding the Australia reading also leaves Mount Washington's 231-mph wind gust the top gust in the Northern and Western hemispheres, according to the World Meteorological Organization.

"The fact that the 1934 Observatory crew could accurately measure a wind of this magnitude, during a period of very heavy glaze icing, is a tribute to their planning and engineering acumen, as well as their commitment to establishing and maintaining this remote scientific outpost," Mount Washington Observatory said in an article.

For the latest weather news check back on Watch the AccuWeather Network on DIRECTV, Frontier, Spectrum, fuboTV, Philo, and Verizon Fios. AccuWeather Now is now available on your preferred streaming platform.