Why Mount Washington Has Some of the Most Extreme Weather in the World


Mount Washington boasts the second fastest recorded wind on Earth at 231 mph.

Mount Washington. NH State Park

After an unusually chilly weekend in June, the past few days of good weather are a welcome change. Unfortunately, the same system that kept temperatures below 70 degrees on Saturday and Sunday brought severe cold and snowy weather to New Hampshire’s Presidential Range, including Mount Washington.

Sitting at 6,288 feet above sea level, the weather for New England’s highest peak is often dramatically different from the weather in the valley below. Mount Washington is often cited as having the most extreme weather in the world and that is not necessarily an exaggeration.

Although we experience weather here on land, that weather is made up of a large interaction between layers of air from the surface to the tropopause at an altitude of about 30,000 feet.

There are many factors that drive extreme weather to the summit of Mount Washington. Most notably, the summit is the highest peak in the region and sticks into the atmosphere without anything to slow the wind. The lack of trees at this altitude is included in this equation of extreme weather. Once you get above about 4,200 feet, the landscape turns mainly to rocks, mosses and lichens, and small plants.

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The summit of Mount Washington is often covered with clouds and fog.

In fact the flora of Mount Washington is more suited to the alpine regions of the suburban areas.

With nothing to slow the wind, it can blow quite hard and often reaches speeds of over 100 mph. Mount Washington boasts the second fastest recorded wind on Earth at 231 mph.

There is a scientific theory called the Venturi effect, whereby liquids are squeezed and move faster. Air is a liquid; As the wind blows through the Presidential Range, the mountains begin to squeeze it. As Mount Washington sits above everything else, it feels the Venturi effect most dramatically.

Earlier This Week A Strong Jet Stream Swept Through Much Of New England, Including The Top Of Mount Washington In New Hampshire.
Earlier this week a strong jet stream swept through much of New England, including the top of Mount Washington in New Hampshire. tropicaltibits

There’s also an extra squeeze of air from the top of Mount Washington’s summit. Upwards, the tropopause meets the stratosphere. Although the jet stream itself is very high, low level jet streams can form at altitudes of about 5,000 feet, producing dramatic wind.

For every thousand feet of elevation, the temperature drops by about 3.5 degrees, so by the time you reach the top of Mount Washington, it’s much cooler than the valley below. This weekend, cold air masses and wind brought air chill in the single digits with more than an inch of snowfall.

Temperatures At The Summit Of Mount Washington Were 20 Degrees Cooler Than At The Base Early Tuesday Afternoon.
Temperatures at the summit of Mount Washington were 20 degrees cooler than at the base early Tuesday afternoon. Mount Washington Observatory / MOUNTWASHINGTON.ORG

The position of Mount Washington in New Hampshire and apparently much of New England is at the confluence of several different jet stream patterns. This is one reason why the weather in New England is often so variable and why Mount Washington’s weather is particularly extreme.

Strong polar and subtropical jet currents and even a rapid zonal or west-to-east pattern will often pass through the part of New Hampshire that often leads to the extreme weather Mount Washington and New England are known for.

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