How Windy is “Very Windy?” by Philip Werner

 

When planning above-treeline hikes, particularly in winter, we pay particular attention to two variables: temperature and wind speed. The best source for this information is the NOAA National Weather Service forecast available on weather.gov which covers all of the United States. You can use that website to do point forecasts as well on trails, ridges, or mountain summits. It’s amazingly accurate most of the time.

Give it a try by typing “Franconia Ridge” into the upper left-hand text box next to the button labeled “Go”

Franconia Ridge Forecast

It’s important to understand that the National Weather Service (NWS) forecast shown above, uses a highly stylized vocabulary that has very specific meanings. Many of these terms and abbreviations are used by NWS forecasters to communicate with each other and have been in use for many years.

The NWS publishes a glossary that is handy to refer to containing definitions for more than 2000 terms, phrases, and abbreviations used. It’s important that you understand what they mean when they use different terms to describe the wind, especially in winter, when the resulting wind chill can accelerate frostbite on exposed portions of skin or knock you to the ground in hazardous terrain.

For example:

• Very Windy means 30-40 mph wind.
• Windy means 20-30 mph wind.
• Blustery or Breezy means 15-25 mph wind.
• Calm means no wind.

Hourly Forecasts

While the NWS provides a daytime and nighttime forecast, as shown above, they also provide tools to forecast conditions by the hour, as well as ahead by several days. This is very useful for forecasting what conditions will be like when you reach a certain point during your hike. You can find this tool by scrolling down the page below the main forecast on weather.gov.

The hourly forecast is useful because wind speeds tend to vary during the day. If you can stay below treeline, protected from the wind by vegetation when the winds are high, you may be able to time your hike so that you pop above treeline just as the wind speed is forecast to drop. I’ve done this many times when climbing higher mountains where it takes several hours to reach treeline.

You can use the same tool to predict:

• When precipitation is expected to fall and by how much
• Wind Chill
• Dewpoint
• Temperature
• Wind Gusts
• Wind Surface Speed
• Relative Humidity
• Precipitation Potential
• Sky Cover
• Rain
• Thunder
• Snow
• Freezing Rain
• Sleet

When is the Wind Dangerous?

The wind can be quite dangerous, particularly in cold weather, because it can accelerate hypothermia or other cold injuries like frostbite. Personally, I avoid hiking in warmer weather in sustained winds (not gusts), above treeline, that are greater than 40-50 mph where there’s no vegetation to provide cover. That’s the wind speed where you can feel the wind pushing you around. In winter when there is an elevated risk of frostbite, I like to avoid wind speeds of 25 mph or more and temperatures below 10 degrees F. But those are my preferences based on years of experience. Those might sound like conservative wind speeds and temperatures but those are the basic rules of thumb that I follow.

But there are situations where I will hike in higher winds. For example, in summer, the risk of cold injuries is much reduced and hiking in higher winds can provide some relief. I will also hike in higher winds in winter out in the open for short distances, when the wind is at my back, or when I know that certain terrain features provide a wind break. But these factors depend on knowing your route in great detail through planning or previous experience.

Net net. Everyone develops their own preferences when it comes to hiking in windy conditions. Hopefully, this overview of the forecasting tools available to you will help you make those decisions for yourself.