Update on the snow drought

The snow water equivalent is below 50 percent in parts of the southwestern quarter of the U.S.

Snow Drought, April 11, 2021
Snow Drought, April 11, 2021.

I learned years ago that it is folly in February, March, or April to attempt to predict the outcome of the summer/fall wildfire season in the Western United States. If the weather in the summer is relatively cool and wet, the fire season will not be extremely busy.

Having said that, a glance at the snow water equivalent dated April 11 shows that it is far below normal in the Western states except for Washington, Oregon, Montana, and northern Idaho.

It is below 50 percent in some areas of California, Utah, Arizona, South Dakota, and New Mexico. In southeast Arizona it is zero to four percent of average.

Couple that with the higher than average temperatures and lower than average precipitation expected in some of these areas and, dare I say it, if the predictions are correct, there could be more wildfire activity than average in the southwestern one-quarter of the U.S. this year.

The following outlooks were produced about three weeks ago, so they should be taken with a grain of salt.

Precipitation outlook May through July, 2021
Precipitation outlook May through July, 2021.
Precipitation outlook, May through July, 2021
Precipitation outlook, May through July, 2021.

Winter weather — precursor to the 2016 wildfire season

Above: precipitation last 90 days, percent departure from normal. Click to see larger version.

There are three main factors that influence the behavior of a wildland fire: weather, fuel, and topography. Thankfully topography does not change from year to year in any significant manner. If it did, the job of wildland firefighters would be incredibly more difficult. Weather and fuels (vegetation) do change, not only from year to year from but from day to day — even hour to hour as the fine fuels absorb moisture out of the air. The weather is infinitely variable and has a huge effect on fires and fuels. This turns many firefighters into amateur meteorologists in an effort to master their craft and keep themselves and their colleagues safe.

Often at this time of the year as preparations are under way for the western wildfire season we look back at the winter weather.

There is little doubt that precipitation and temperature over the last 90 days will have an effect on summer fires. Many media outlets find it hard to resist the temptation on a slow news day to exaggerate how, for example, a dry winter might lead to disastrous wildfires. But the fact is summer weather has a greater effect on the number of acres burned than the conditions six months before. Hot, dry, and windy conditions in the summer are usually associated with a busy fire season.


As you can see in the map above, large sections of the forested areas in the northwest had above normal precipitation over the last 90 days. There are regions in Montana, Washington, and Oregon that had 150 to 200 percent of average. However, much of the southwest, southern California, and areas within the states of Colorado, Utah, Nevada, and Wyoming were below normal.

CA reservoir levels 3-14-2016
Water levels at selected California reservoirs, March 14, 2016. California Dept. of Water Resources.

Heavy rain this winter in northern California, 110 to 150 percent of normal, has been adding a lot of water to the reservoirs that have been in pretty bad shape for the last couple of years. The two largest reservoirs in the state, Lake Shasta and Lake Oroville, have both refilled to levels above the historical average and are 81 and 73 percent full. Most of the lakes farther south have some serious catching up to do.

Snow Cover

Snow Cover 3-15-2016
Snow cover on March 15, 2016. Rutgers.


Snowpack, March 1, 2016
Snowpack, March 1, 2016

California snowpack lowest on record since 1950

CA drought

California’s snowpack has reached an all-time low since 1950, the California Department of Water Resources announced last week.

Like most states in the West, the department takes regular snowpack measurements, which are used to predict the amount of water California can expect to see in its reservoirs. The measurements are also an indicator of how dry and possibly fire-prone California’s landscape has become.

California’s snowpack accounts for 30 percent of the state’s water, once it melts, the release said.

Snowpack measurements are taken against an average — at 100 percent — making anything less than 100 less than average. California’s snowpack has been on a steady decline since January of this year. The latest measurement was 8 percent of the historical average. Typically, snowpack is at its peak in California by April 1.

The state is going into its fourth year of extreme drought, following three of its driest years on record.



UPDATE: Rekindled controlled burn caused Montana fire near ski area

Update 5:30 p.m. MDT: 

New maps have updated the West Fork fire perimeter to 400 acres, down from an estimated 700 as of Saturday night.

Seventy people are working on the fire, including crews from Red Lodge Rural 7 and the U.S. Forest Service. Crews determined that the fire threatened 30 structures, although none were damaged or destroyed. There were no evacuations on Sunday and the Red Lodge Mountain ski area was operational on Sunday.

The fire was estimated to be 20 percent contained as of early Sunday evening. In a post on its Facebook page, Red Lodge Fire Rescue said:

“(The) fire was believed to have been rekindled from a controlled burn that was started last (Wednesday), when there was still snow on the ground. Yesterday’s high wind and temperature brought it back.”

fire image


Original post:

A wildfire a few miles from the southern Montana town of Red Lodge forced a brief evacuation of the local ski area, Red Lodge Mountain, on Saturday afternoon, the Billings-Gazette reported. 

A controlled burn on private land might have ignited the wildfire when it was fanned by winds and spread out of control on Saturday. Incident reports show that fire was human caused, with an investigation on-going. By Saturday night it had burned more than 700 acres.

Officially named the West Fork fire, the blaze has been working its way through timber, grass and sagebrush. The ski area was evacuated around 2:30 p.m. as a precautionary move and to allow fire crews better access, a spokesman for the U.S. Forest Service told The Associated Press. 

The ski area was closed for a few hours; officials with Red Lodge Mountain said that the area will be open on Sunday.

Conditions at the resort are warm and dry, and it has been more than three days since the area last saw snowfall, according to forecast histories. Snowpack in the Upper Yellowstone basin, where the ski area is, was below average, according to the most recent measurements taken by the Natural Resources Conservation Service.

The basin’s snowpack came in at 89 percent of normal as of measurements posted on March 29.

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