What happens when it rains in California

The weather headline this¬†winter has been the rain in California. A month of rain has added water to reservoirs, snow to the mountains, and mud to places it is not supposed to be. But what happens in California doesn’t necessarily stay in California, and the atmospheric river pushing into California has resulted in some interesting weather in the Midwest: wet and warm.

Notably, the City of Lakes Loppet’s Luminary event has been pushed back, because the heavy, wet snow and lack of cold air has kept the lakes from freezing as solid as they usually do (whether the City of Lakes Loppet will be able to cross the lakes in a few weeks is still an open question). Closer to home, the Birkie needs to cross the final two miles of Lake Hayward to reach Main Street, and if the ice is thin, the race can not fully take place. The race has been shortened to OO twice (2007 and 2017), but several more times it has not crossed the lake, including four times between 1983 and 1991.

Most of these years have been due to a lack of snow on the latter portion of the course, with races ending (or, in some cases, starting, since the course changed direction in those days) at Duffy’s or Rosie’s field. In most of those cases, the winters were warm and dry, and a warmup later in the season led to a lack of snow. 1983 had more snow, but a warm February appears to have affected ice on the lake, which may never have thickened below a thick blanket of snow.

In recent memory (the past 25 years), there have been five cancelations:

  • 1998: A warm February leads to a short course.
  • 2000: A warm and rainy end of the month cancels the race
  • 2002: A warm, dry month ends with enough rain to shorten the race
  • 2007: A couple of warm days and low snowfall creates the half-length open-track rock ski race
  • 2017: A warm spell and rain cancel the race

Since the first Birkie, San Francisco has gone over 30 inches of rain in 1973, 1978, 1982, 1983, 1997 and 2017. Of these, six years, three correlate to some sort of Birkie disruption. So there appears to be some correlation between heavy rain in the Pacific and Birkie disruptions. In this year’s case, the warm Pacific air has led to plentiful snow in the Northwoods with warm temperatures. And while snow is good, we’ve had perfectly good Birkies in years like 2012 and 2015 with lower snowfall.

What do I take from this, reading tea leaves a few weeks from the race? Right now, cold is more important than snow. The dense snowpack should be able to withstand all but the worst meltdown. More snow? Sure. But it would be better to freeze up the base and freeze up the lake rather than having to worry about snowmelt and ice. At least the current outlooks call for some colder weather building across the country (less of a polar vortex outbreak and more of a lasting cold) which might be enough to push through the lake snow cover and freeze things down.