Tuesday, December 28, 2021

A History of the Drought in Three Pictures.


Castle Crags on December 27, 2021
It's nice to be able to report some good news once in a great while. Global warming models for California paint a truly depressing picture going forward of crippling droughts, failing snowpacks, and many tough choices to make regarding water use. We've been living those models for the past few decades with a five-year drought ending in 2017, and one of the worst drought years in history just last year. We are coming to depend more and more on the occasional intense atmospheric river events to fill reservoirs in preparation for the dry years. They've been in short supply in recent years.

My family-related travels have encapsulated the story of California's precarious water situation. The pandemic had prevented many forays north to Oregon and Washington, but we managed a trip last April, and we just completed a rather harrowing trip today. These trips were a lesson in contrasts.

We always try to take a break at Castle Crags State Park near Dunsmuir and Mt. Shasta. The granite peaks are geologically the equivalent of the Sierra Nevada, but geographically they are part of the Klamath Mountains (which were displaced west from the Sierra millions of years ago). The Crags are shorter than the adjacent Sierra Nevada, but the loftiest peaks reach 6,500 feet, which allowed for glacial erosion during the Pleistocene Ice Ages.

Castle Crags on December 18, 2021
When we visited last April, the forest surrounding the crags was frighteningly dry (below). What should have been a damp forest floor with streams swollen by meltwater was like a tinder box waiting for the spark that would ignite an inferno. Like the rest of the mountains surrounding the Central Valley, the snowpack was gone, literally 5% of a normal year. 

When we left on our trip on December 18, things were looking up a little. There had been a surprising strong storm in late October that had dropped some snow on the mountains, but warmer weather had melted much of it. A dry November left the snowpack at 19% of normal.

Then a bunch of storms coincided with our trip plans. When we stopped in at Castle Crags on December 18th, there was a delightful cover of snow on the peaks (the picture above). It seemed a promising beginning of a decent snowpack.

We were in Seattle area at the beginning of one of the biggest snow events in the city's history. We left the city on freeways so covered in ice that the lane dividers couldn't be seen, and everyone guessed (only somewhat correctly) where those lanes were. Spinouts and accidents were everywhere, and it took us nearly four hours to go the first hundred miles towards the south. We eventually outran the storm but stopped for the night in Oregon were the storm caught back up to us. 

Our next day was 380 miles of icy anxiety, but luckily the roads were clear when we reached the top of the Siskiyou Mountains and Mt. Shasta. But what huge amount of snow had fallen! Looking at the top photo in the post, you can see the high peaks were literally coated in snow.

Castle Crags on April 23, 2021
In a more official vein, the Sierra Nevada had jumped from 19% to 159% of normal snowpack in the space of three weeks (below). We've received the 52% of the total amount of snow year, with three normally wet months to go. And at least two more storms are forecast in the next ten days. It's really good news, a possible respite from the long-term drought that has been gripping the region. But it's a real mess if you have to be traveling in it.

Source: Snow Pack Conditions - Snow Water Content Chart (ca.gov)
But the snowpack is not the whole story. Reservoirs across the state reached critically low levels in two years of drought (below), and it will take more than a couple of good storms to build them up again. A heavy snowpack is great, but warm periods can prematurely melt and evaporate the ice. I'm going to stay optimistic, but my mind is telling me that this is a respite, not a solution to our problems. If we get a good water year, we will still face imminent droughts and depleted groundwater reservoirs. We need to face the problems, and not put them off. 

Source: Interactive map of water levels for major reservoirs in California | American Geosciences Institute
But it sure was nice to see all that snow!


Kathy Crawford said...

Your first 2 photos the dates are off by 900 years 😉

Garry Hayes said...

Ten-fingered typing doesn't work as well when the little finger doesn't stretch right...thanks for the correction!