The snow level was still down to 4,500 feet the other day as a typically wet June weather pattern settled across the Pacific Northwest. The spring precipitation will add to another good year of snowpack in the mountains, one of the benefits of a La Niña weather year. Still, climate projections paint a bleaker picture for next year's weather patterns.
Most of us know that snowpack in the mountains is like a giant water bank. Snow piles up in the mountains, then melts to provide water for Washingtonians, irrigating eastern Washington farms, watering lawns and urban household gardens. In addition to all this water, good snow provides a boost to the economy in winter months, when ski areas bustle with skiiers and boarders.
This spring Crystal Mountain tentatively plans to remain open on weekends through July 1. “We are one of only two places in North America still offering lift serviced skiing,” Crystal reported on its web site. “The snow has melted at the base area, but there's still plenty of snow and great coverage up top."
According the Climate Prediction Center at the National Oceanic and Atmospheric Administration (NOAA), La Niña is fading and there is a 50-50 chance of an El Niño weather pattern developing this fall.
Why pay attention? As Cliff Mass, regional weather guru writes, “El Niño years tend to be drier, with less snow in the lowland and mountains, and weaker storms.” That can translate not just into bad skiing years, but into drought-like conditions come summer.
Just a few years ago, in 2005, weather patterns were similar. “What a year to remember, certainly one for the record books,” read the Basin Outlook Report for June. “Records set over 30 years ago and thought to be un-breakable fell by the wayside during this unprecedented year of low snowpack, precipitation and runoff.”
The early 1990s were also host to several years of low snowpack, leading Seattle City Light to impose a “drought surcharge” to cover the impact on utility revenues. That's in comparison to typical summers, when Seattle City Light actually sells its excess hydropower to California and Arizona, which have peak demand in the summer because of air conditioning.
By contrast, our winter weather of the past two years has been driven by La Niña, which tends to pile up the snow in the mountains, especially after the first of the year. In 2011 April and May set snowfall records, dumping 200 percent of average snowfall in some places. Cool temperatures meant snowpack levels were sustained well into the spring, as described in the June 2011 Basin Outlook Report from the National Resources Conservation Service:
“Though all basins are above the 30-year average it is important to keep in mind that this mostly is not due to excessive late season snow accumulation but the extreme lag of normal snowmelt. Another way to look at it is that normally Washington would have about 40 percent of the peak snow accumulation still on the ground, meaning that 60 percent would have (already) melted. As of June 1 (2011) that number sits at 97 percent which means that we still have almost all of an ‘average’ snowpack to melt out.”
Through this summer at least, water should be plentiful. The “water year” usually runs from October through September of the following year. This June’s Basin Outlook Report is the most recent for this "water year":
“For the most part we experienced above average temperatures and dry conditions the first half of the month with the second half bringing wetter and cooler than normal west side weather and dry and cool on the east side of the state. The snow is melting at a pace to rival ‘watching paint dry,’ however we still have only 50-75 percent of what we had on the ground at this time last year."
Snowpack is tracked using instruments called SNOTELs that measure snow depth and water content at hundreds of sites around the state. While June 1 statewide SNOTEL readings were 182 percent of average, experts caution that at this time of year, that can easily change — both with additional snow (which is rare) and snow melt (the usual condition).
“As temperatures warm the melt rate will increase, rapidly changing percentages on a daily basis,” NRCS said. “Numerous lower and mid elevation sites have already melted out and by the time this article is published [June 8] even more will have melted. That’s not to forget the higher elevation sites that still have over 20 feet of snow and won’t melt out until late July or August, providing fresh runoff throughout the entire summer.”
The NRCS' point is well-taken. The Nooksack Basin in northwestern Washington had the highest snow-water content of any reporting station on June 1, with 84 inches (well above the 49.6 inch average). By June 21 it had dropped to 64 inches.
It's likely that projected summer climes will only accelerate the melting. The Climate Prediction Center is forecasting abnormally warm and dry conditions in most of the Pacific Northwest through the next several months.
With relatively high snowpack this year, there are few concerns about water in 2012. Meanwhile, we all await the traditional start of summer in the Northwest — somewhere around July 10. Still, if the El Niño does form, get ready for change.