What causes such sudden strong winds in Idaho that last for HOURS on end?

Question Asked by students from Beutler Academy

Answered by Tim AxfordWarning Coordination Meteorologist – NWS Pocatello

Here in Idaho, we’re no stranger to windy days, but so many of us just go through the windy days without thinking about what causes it and why are we so prone to windy days in Idaho? To understand what makes Idaho so windy, we’ll first have to get back to the basics and explain what wind is and how it develops.

Basics of Wind: In short, our atmosphere (the air all around us) is out of balance. Uneven heating of the atmosphere creates areas of high and low pressure that range in size from really really big (the size of many states) to really small (the size of cities). The reason this is important is that in trying to balance the atmosphere, air moves from areas of high pressure to areas of low pressure. Generally, the greater the difference between the two areas, the stronger the air movement (wind) is. While the wind in your backyard really depends on some of these broader weather patterns, most of Idaho’s windy days can be attributed to two primary factors – Seasonality and Terrain.

Seasonality
Idaho is a true four-season state. Spring and Autumn are seasons of strong temperature and pressure transitions and when we typically see our biggest wind storms in the Gem State. We may have several days with high pressure, followed by a strong cold front that brings cooler temperatures, rain, snow and inevitably wind. The origins of this wind is directly related to the basics outlined above going from high pressure to low pressure in a relatively short time period. It is typically during these events when the wind will continue to be strong day or night, only weakening when the weather transition weakens.

Terrain
We can’t ever talk about weather in Idaho without mentioning terrain which has some of the biggest effects. In Idaho, most of us live in valley locations, whether we’re in the Wood River Valley, Teton Valley, or the Snake Plain (a broad valley). Valleys tend to gather and funnel wind which can strengthen the overall wind speeds. We see this a lot when a low pressure system moves in from the west. We’ll see wind from the south strengthen and funnel up the Snake Plain, with some of the strongest winds found over the Arco Desert. To make things windier, add in that we don’t have a lot of trees or buildings to provide much friction against the wind (this is why it always seems windier in a field or on a lake than in a city). In addition to funneling the wind, low valley locations heat up much faster during the day than higher terrain leading to temperature stability and pressure differences. This is often why we’ll see strong uphill/upvalley winds during the day and weak or even reversed downhill/downvalley winds overnight. Most nights, the atmosphere can cool and stabilize, leading to weaker winds.

Overall, there are many factors that go into forecasting what the wind will do each day but with the large impacts wind can have on wildfire, transportation, recreation, and really just about everything we do, we think it’s a worthy effort. We hope this answers your great question!

You can track real time winds (and other weather conditions) here: http://www.wrh.noaa.gov/map/

Beaufort Wind Scale

The Beaufort Wind Scale is an empirical measure that relates wind speed to observed conditions.

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