Wilderness Skills - Olympia Mountaineers

• White-out. Do not travel. Wait for clearing skies.
• Dense fog. Do not travel. Find shelter.
• Darkness. Do not travel. Improvise shelter and wait for daylight.
• Lightning. Leave high, exposed areas immediately. Crouch down away from trees, caves and cliffs.
• Check on the weather! It's not just the trip leader's responsibility to be aware of the weather; it is every
member of the party's responsibility. Before every trip, listen to the NOAA weather report on a
"weather" radio, or call the local weather phone numbers in the appendix.
Weather Predicting
Below is a compendium of folk sayings, common observations, and "scientific" principles useful in predicting
local weather. The most reliable sources for weather predictions is NOAA Weather Radio or computerized
weather data services (see phone lists ).
• In the absence of any contradictory signs, predict tomorrow the weather
you had today. In our area, the weather frequently occurs in seven-day
patterns; today's weather will likely occur on the same day next week.
• A halo around the moon or sun means rain, usually within 24 hours.
• Red sky by night, sailor's delight. Red sky by morning, sailor take warning.
True? The night part is about 70% accurate.
• Tomorrow's weather usually comes from the west, and when the sky is
clear (no water or moisture), the atmosphere scatters the light at the blue
end of the spectrum, leaving mostly red. Thus, tomorrow's weather is likely
to be good.
• A lenticular cloud cap on Mt. Rainier, or other high peaks, is nearly always a sign of rain, probably
within 24-36 hours. If Rainier is absolutely clear in the afternoon, the weather usually will hold for 24
hours. High cirrus clouds usually mean precipitation possible within 24-48 hours.
• The distinction between thick fog and real storm clouds is not easy to make from a canyon or valley;
but, if it is raining, there is no hope of climbing above the clouds (except on very high mountains).
• Rising fog is not normally associated with the onset of a storm; descending fog does indicate an
approaching storm and, worse, may prevent you from seeing it until too late.
• A steady fall of a barometer (while you are not climbing) is an indication that rain is coming. The greater
the rate of change, the more certain the storm. In worsening weather, an altimeter reads higher, the
opposite of a barometer.
• A rising barometer (while you are not descending) indicates good weather. An altimeter reads lower.
• You can determine the time until sunset by counting the number of your fingers between the horizon
and the sun; each finger equals approximately 15 minutes.
• The driest time of the year is the last 10 days of July and first 2 weeks of August.
• You can estimate the temperature where you are going:
o
o
o
As elevation increases, temperature generally decreases at approximately 3.6 degrees per
1,000 feet of elevation:
5 degrees Fahrenheit for each 1,000 feet of elevation in dry, stable weather,
3 degrees Fahrenheit for each 1,000 feet of elevation in moist weather.
• If hot air rises, then why is it always cooler in the mountains? Because as hot air rises, it cools. On its
way skyward, decreasing atmospheric pressure causes it to expand and, consequently, gradually grow
colder. Air is warmed mainly by sunlight hitting the Earth's surface. The farther you get from the radiant
Wilderness Skills Module Page 63 of 73
Olympia Mountaineers - Hiking, Alpine Scrambling and Basic Climbing