Concerns Rise About The Limited Mountain Snowpack

There may be some water supply and wildfire issues that unfold in summer and fall. This was a second La Nina winter season in a row. La Nina winters usually result in a healthy mountain snowpack and the winter of 2020-21 did just that, ranging from about 110 to 135 percent of average.

This winter season, the wet period from late November into mid-January resulted in a mountain snowpack that ranged from 100 to 130 percent of normal. Recall that the Cascade pass highways closed several times due to heavy snow and high avalanche danger.

Then in mid-January, a relatively drier weather pattern became established and continued into mid-February. The month long mid-winter drier period resulted in putting a dent in the snowpack, falling behind average and dipping to 65 to 95 percent of average by mid-February.

The mountain snowpack usually reaches its peak around April 1st. So there was not much time for the mountain snowpack to catch up after the drier mid-winter weather pattern turned wetter.

The latest statistics from the Northwest Avalanche Center show that the mid-winter dry period suppressed the snowpack. As of April 1st, the snowpack in the Olympics and Cascades ranged from 60 to 85 percent of normal. Early this week’s healthy storm will add a foot or so of new snow to the mountain snowpack, but still not enough to reach at least average in most locations.

The more limited mountain snowpack may offer some challenges this summer and fall. One concern is an earlier start to the wildfire season, likely in July. The North Sound has suffered periods of wildfire smoke and poor air quality four out of the last five years after decades of no wildfire smoke issues. Nearly all that smoke was blown into the region from wildfires in British Columbia, Eastern Washington, or from the south in Oregon and California.

The lower than average mountain snowpack also means less available stored water in the snowpack. The April 1st Natural Resources Conservation Service mountain snowpack water equivalent map shows Olympic and Cascade mountain basins ranging from 56 to 97 percent of average. This issue raises concerns regarding water for irrigation, fish, recreation, and consumption into this fall.

The latest seasonal weather outlook from the National Weather Service’s Climate Prediction Center (CPC) again shows what has been the trend thus far this century, a warmer than average July through September. The odds on another ‘heat dome’ similar to one experienced in late June last year are remote, but cannot be ruled out.

Historically, the North Sound has periods of temperatures rising into the 90s averaging three times per year. But so far this century, the North Sound has exceeded that average more than half the time, and periods of excessive heat will be another concern this summer.

The outlook also shows near average precipitation this summer. Summertime is the driest time of the year.

Looking toward this fall, the current La Nina evolves to Neutral conditions, meaning the sea surface temperatures in the Eastern Pacific Ocean have good odds on being close to average. Neutral conditions lie in between La Nina (cooler than average equatorial Eastern Pacific sea surface temperatures) and El Nino (warmer than average).

The latest CPC outlook for this fall shows the odds for precipitation tipping toward drier than average conditions with temperatures leaning toward warmer than average. Usually Neutral conditions produce near average temperatures and precipitation, along with a greater chance for significant fall storms like strong winds and flooding.

In the meantime, prepare for what may be another warm summer with a greater chance of wildfires and wildfire smoke later this summer, along with more limited water supplies.

North Sound Meteorologist Ted Buehner worked more than 40 years for the National Weather Service (NWS) from 1977 to 2018. He is now an Everett Post Media team member. Together with Everett Post Weather Minute Podcasts, he provides morning and afternoon commute traffic and weather updates on both KRKO and KXA Radio, and sports reporting on KRKO.