Water Matters: With snowfall, size matters

This is not about federal politics, nor the passage of the school levies — though both are big topics for discussion. To be honest, it’s more about structure.

Today I’m writing from eastern Washington, where my family comes each February with friends to enjoy skiing on groomed tracks and trails, where we can stretch out and cruise for hours along the valley bottom and gently rolling hills.

I also was going to say where we can rely on cold, crispy snow that our skis glide on with little effort. But this trip has been an exercise (a long workout in fact) in shoving Cascade Concrete with human muscle and marginal help from skinny strips of plastic attached to our feet. Snow — with very little ice.

Ice crystals are what make “good snow” good. Tiny but strong, they can compress to a certain degree, by the weight of more snow or by skiers, and still keep enough structure that tiny air pockets expedite the glide of a ski.

But too much thaw and the crystalline structure is gone for good. The air pockets fill with water and the snow surface seemingly sucks on the passing ski, slowing down both ski and a frustrated skier.

In Sequim we had a colder than average winter with snow at the mid-elevations lasting for weeks rather than days. We and our neighbors were skiing literally cross-country wherever a plow or sander hadn’t yet traveled, and rocks rather than ice crystals were our biggest concern. Seems like just last week I was shoveling the berm from our driveway for the third time.

But with a rise in temperature, our precipitation turned to rain. A Pineapple Express passed through and suddenly frogs were hopping across the road in a rainstorm as if it were spring.

The cold weather and lack of persistent rain meant a very late start for our ephemeral Bell Creek, which finally started flowing for good on Feb. 6, two or three months later than recent years — finally bringing an end to my fixation on its lackadaisical behavior. It’s good to see it running.

In the Olympics, the thick, white blanket over Greywolf Ridge has visibly thinned. Even in this cold winter, at the Dungeness SnoTel site, elevation 4,000 feet, there have only been 26 days that the low temperature has stayed below freezing. On some recent nights it never dropped below 40 degrees — bad news for ice crystals.

Skiers on Baldy this week would likely feel some suction as they glide and need to push heavy snow as they carve turns. I doubt they would care … being thrilled to see a good snowpack and only concerned about avoiding rocks.

Indeed, structure matters … for skiers, the federal government and Sequim School District.

Geek Moments

From the National Snow and Ice Data Center:

When glacier ice becomes extremely dense, it absorbs a small amount of red light, leaving a bluish tint in the reflected light, which is what we see. When glacier ice is white, that usually means that there are many tiny air bubbles still in the ice.

After about two winters of compression, the snow turns into “firn” — an intermediate state between snow and glacier ice. At this point, it is about two-thirds as dense as water.

For the 2017 water year (started Oct. 1), on Feb. 19:

• In Sequim, cumulative rainfall = 7.8 inches.

• At the SNOTEL station (elev 4,000 feet), snowpack = 20 inches (same as a month ago); snow water equivalent = 7.7 inches (up 1.7 inches from a month ago). Days/nights below freezing = only 26.

• Dungeness River at Mile 11.8, flow = 850 cfs (the tail of a rainstorm). Bell Creek flow at North Blake Avenue = about 1 cfs; at the mouth = 2 cfs. (1 cfs is just =N:E= gallons per day)

Ann Soule is a licensed hydrogeologist immersed in the Dungeness watershed since 1990. She is now resource manager for the City of Sequim. Reach Ann at columnists@sequimgazette.com or via her blog of Gazette articles at watercolumnsite.wordpress.com.