Mountain WeatherMITOC Winter School 2002
Robert Zeithammer
Why Weather?
October 12, 1999 …top of Mount Madison
Weather Changes
• January 1: Temperature 3 degrees;• Snow, freezing fog, wind chill –50• Visibility: 100 feet
Moosilauke Skiing Trip, Winter School 2001
Weather Safety
• Check the forecast (but don’t rely on it!!!)– http://met-www.cit.cornell.edu/cgi-bin/fcst?NH004– http://www.mountwashington.org/weather/today.html
• Daily weather-report• Higher-summits forecast• Backcountry conditions
• Stay alert to weather changes– Clouds and winds provide big hints
• Come prepared for the worst!!!
What’s “worst”?• 30 F, heavy rain, any wind a bonus
• -10 F, 60 MPH wind : feels like –50F
Mount Washington at the confluence of three major storm-tracks.
In the Whites, wind is the biggest concern.– It makes you cold (wind chill)– It knocks you over (70 MPH enough)– It likely makes visibility unreliable– It increases avalanche danger
Exact #s unimportant. Basic idea crucial!
Presidential
Reverse,
February 2001
Mountains get bad weather
Cirrus Clouds
High altitude clouds; good weather, possible rain in 12-24 hours for some types
Cumulus Clouds
• Nice weather, but keep an eye out
Nimbostratus Clouds
• Lower (2000m) clouds
• Rain or snow coming soon
Cumulonimbus
Clouds with vertical growth (“Anvils”)(May not see the anvil when close)Heavy rain, snow, hail, lightning!
Blue Skies
• Good weather has its downsides too: The Sun (it’s a mass of incandescent gas…)
• Sunburn can be serious– Light and U/V reflected by snow and ice– Sunburned retinas and mouths are not fun
• Sunscreen, long-sleeved clothing, and sunglasses will make you happier
Weather Summary
• Check forecasts, check the skies often– Neither is a perfect predictor, so be prepared.
• Take-home lesson: STAY ALERT. Weather changes rapidly.
• When in doubt, RETREAT!!!