RMC Newsletter - Summer 2004

Mountain Weather of the Northern Presidentials
By Steve Bailey

There’s something different about the weather in RMC country. Winds blow harder, snows fall deeper, and temperatures drop farther.

The explanation is quite simple: the rugged relief around Randolph represents one of the few obstacles to weather systems passing from west to east. As a result, winds are regularly churned into gales as air gets pressed through notches and squeezed over crags. Winds and moisture conspire to produce deep snows and soaking rains, and this conspiracy is no theory! In mountain ranges the world round, moisture, forced upslope by the wind, cools, condenses, and falls leaving more prodigious amounts of precipitation on windward slopes than on leeward slopes.

Moisture-laden easterly winds off the Atlantic Ocean often deliver the heaviest precipitation totals when they collide with east-facing slopes in the White Mountains. Randolph, whose valley opens to the east, has the weather records to prove it. On November 23, 1943, a snowstorm dropped 56" of snow in 24 hours on Randolph, which stands as a New Hampshire single snowstorm record. This past December, Randolph again topped the state’s list of snowfall totals, recording 38" of white stuff after just digging out from a separate nor’easter a week earlier.

In addition to snow, temperatures tend to fall in RMC country too. Indeed, the coldest temperature recorded in town was –30°F (February 1943) and the coldest on
Mount Washington –47°F (January 1934). The town of Randolph sits in a corridor where cool air pools on clear, windless nights. Since heat stored at the earth’s surface is released at night, valley floors become “frost pockets” when there are no clouds to trap the released heat, particularly if snow covers the valleys, cooling the air around it. The irony of this phenomenon is that areas situated slightly above the valley floor—areas like Randolph Hill or The Log Cabin—will record markedly higher temperatures, which is why the phenomenon is called a temperature inversion. Take a hike upslope or downslope on a cloudless and windless night in winter and feel the difference.

During the summer, temperatures on RMC trails tend to be cooler for other reasons too. The northernmost counties of New Hampshire and Vermont are said to be as cloudy as the Olympic Range in Washington, which is due in large part to the Green and White Mountains’ effect on the weather. One of the highest populated areas in the Northeast, Randolph is further deprived of warm air by its elevation; indeed, as air rises, it cools about 3°F for every 1000 feet. Thus, all other conditions being the same, folks on Randolph Hill can experience temperatures 6°F colder than folks near the seacoast, simply because the air is slightly thinner. Of course, even though Randolph no longer has an official weather station, everyone knows that it’s really windy in the valley sometimes! Again, this is due to the surrounding mountains. The strong and sometimes gusty winds keep the town, especially the treeless areas, cooler by way of convection. They also help with the black flies.

While thermometers, anemometers, and barometers all bear testimony to Randolph’s unique weather, so do the town’s surrounding natural features. A hike into Ice Gulch or up to the Ice Caves in King’s Ravine attests to the colder air and less intense light in the North Country. The subalpine spruce and fir along the Kelton Trail give clues as to the annual snowfall levels. “Lichen lines” along their tree trunks indicate how deep snow accumulates in average winters. Since lichen cannot live without at least some light (even in winter), it does not grow under a certain average snow line, where there is no light in winter. Hence, the telltale lichen lines.

Higher up the mountainsides, angular rocks betray the process of frost wedging, where cyclical freezing and thawing of water within larger rocks has split them into blocky, smaller ones. Similarly, the presence of felsenmeer (German for “sea of rock”) testifies to the imperceptible movement of entire mountainsides—the result of thousands of years of frost wedging. The strange shapes the felsenmeer sometimes assumes (circle or polygon) are not the handiwork of aliens but rather the result of frost wedging influenced by local topography. And the seemingly out-of-place stand of krummholtz (small alpine trees) reveals a spot where some lucky seed found just enough shelter from wind, cold, and snow to thrive.

These natural features and the climatic conditions that engender them are worth a closer look, especially since they’re visible from the trail or from home. But, although weather is easy to observe, it’s not easy to predict, so leave the forecasting to experts. In the inimitable words of Yogi Berra, “Prediction is difficult, especially when it comes to the future.”

Though written by Steve Bailey, this article was largely informed by the thoughtful work of Peter Marchand and Jack Stewart. Steve Bailey is an RMC member, former Mount Washington Observer, and former White Mountain Wilderness Ranger. He lives in Boulder, Colorado, and enjoys witnessing temperature inversions first-hand while running in the Flatirons.

1 Noble McClintock observed Randolph weather from his home just east of Lowe’s Store from 1940 to 1949. He served as a cooperative weather observer for the Weather Bureau. Today, unofficial records are kept by Bill Arnold from his house on Randolph Hill, as well as by Jack Stewart from his summer home on Randolph Hill (when he’s there).