Something that has always stuck with me is, "weather is the convergence of two or more fronts." That is to say it might rain, it might snow on its own, but severe weather is the result of two different and potentially harmless fronts colliding and forming a storm! The more fronts that converge, or the greater the difference in the two fronts, the worse the weather that generally results.
While Mount Washington has notoriously erratic weather, the Northern Presidential’s largely share the same weather. Generally wind gust on mount Washington are slightly stronger because of it's prominence, but if Mount Washington is being hit with 100mph winds, it's not unreasonable based on extrapolation to determine that the neighboring summits are receiving AT LEAST hurricane force winds of 70mph!
Mount Washington and the Northern Presidential’s, including Clay, Jefferson, Adams (and sub summits), and Madison weather patterns are partly due to the convergence of several storm tracks. Along with it's location relatively close to the coast, it's prominence (height above the neighboring land), proximity to converging storm tracks (Atlantic, Pacific, Gulf and Arctic), and it's north-south orientation which prevents movement of fronts by prevailing westerly winds; low-pressure systems are notoriously prone to develop along the coastline in the winter months. The relative temperature differences between the interior Northeast and the Atlantic Ocean, along with arctic fronts drifting in from Canada and beyond are primarily responsible for the diverse and completely unpredictable weather in this region.
Mount Washington holds the world record for surface wind speed, at 231 mph (372 km/h) since April 12, 1934. It's entirely possible stronger winds have occurred on earth. Specifically in F5 tornadoes which often have 300+mph winds above the surface. Winds exceeding hurricane force occur on an average of 110 days per year. During the winter months the weather on the summits of these mountains is exceptionally brutal. With hurricane force winds 2 out of every 3 days, and wind chills often dipping into the -40F/-40C range!
In 2004, the summit registered a temperature of −43.6F/−42.0C and sustained winds of 87.5 mph (140.8 km/h). The resultant wind chill was below -100F!! During 3 day period adjoining the day of this -100F wind chill, the combined ambient temperature, and wind speed, never brought wind chill above -50F at any point!
The summit of Mount Washington spends approximately 240 days per year on average in the clouds. There is measurable precipitation on the summit of Mount Washington 209 days a year. The summit sees an average of 101 inches of rain, and 259 inches of snow per year.
While these numbers might be eclipsed many places in the world in either isolated or routine instances, very few have had the continuous and accurate weather data that this summit has had. There has been a continuously operating weather station on the summit since the 1870s, and it has been a model for weather stations around the world!
Beyond the severe weather, and continuously manned and monitored weather station providing perhaps the most detailed historical and confirmed data of any mountain in the world, there is one other aspect to Mount Washington, and the surrounding Northern and Southern Presidential Ranges ACCESS!
While many mountains and ranges around the world have arguably worse weather on any given day (and I stress arguably), very few see the sheer volume of hikers, climbers and skiers that this range sees. Within the range is some of the best moderate ice climbing in the Northeastern US, as well as some great alpine rock climbs, the most accessible and reliable backcountry skiing (although the Adirondacks are a close, and less crowded second!!), and an amazing alpine experience for hikers and winter mountaineers! This accessibility has allowed many unprepared backcountry explorers to find themselves in over their heads in rapidly deteriorating conditions. The result, while again debatable, has given Mount Washington, and to a lesser extent the Presidential’s a place as the deadliest small mountain in the world!!
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(fully weather sealed) Pentax K10D, Sigma 10-20mm.
