While announcing the good news about Standard & Poor’s improved bond rating for Seattle City Light, Mayor McGinn added something that surprised me.
“Maintaining an AA- bond rating is essential for Seattle City Light to continue providing excellent service for residents of our city,” he said. “But we aren’t out of the woods yet. Seattle City Light is facing serious challenges, including a shortfall in revenues due to a far below average snowpack.”
Local weather media had given me the impression our series of late spring storms had brought the snowpack back close to normal. That would be good news, because a plentiful snowpack means lots of hydropower throughout the summer, and hydropower is cheap electricity. (If extra is generated, City Light sells it and pockets the cash and we all win.)
But not so fast–our snowpack is still feeble, even with snow piled high. The confusion partly depends on what you mean by “snowpack.”
“It simply isn’t true,” sighed City Light’s communications director Suzanne Hartman, when I asked if the storms had made much of a difference. This late in the season, the snow that falls doesn’t have time to consolidate into a harder, compressed mass that acts as a cold “battery” in warmer months. Plus, snowpack isn’t measured simply by inches of snow, but by the “snow-water equivalent”–a dry powder is great for skiing, but it doesn’t represent that much water.
As the graph shows, while precipitation was up, the snow-water equivalent differs. Ultimately, Hartman says, the storms resulted in a change (for the good) of about five percent overall, between City Light’s Pend Oreille and Skagit River Valley basin measurements. And the melt has already begun. Both areas lost almost three inches of snow-water equivalent last week.