The Rain She Comes…

I saw a daunting article this morning (16 November 2024) on the San Francisco Chronicle website. The title of the article —  “Atmospheric river may bring significant rainfall and wind risks to Northern California, West Coast” — was enough to grab my attention. The first graphic was telling.

We’re accustomed to heavy precipitation here in Selma (after forty-plus years of keeping detailed records I know of which I speak), but this forecast is something we haven’t seen during the past several years of drought.

You just gotta love the concept of an atmospheric river. They even have their own scale now to give them validity — like the Richter Scale for earthquakes, or Saffir-Simpson that tells us what we can expect from the approaching hurricane. Cleverly called the Atmospheric River Scale and running from a low of AR1 to a maximum of AR5, the approaching event is estimated to fall somewhere between an AR4 and AR5. Oops.

An atmospheric river used to be called a Pineapple Express. This was based upon the entirely accurate observation that most of them start in the central Pacific in the vicinity of Hawai’i, which is known for many things, including pineapples. For myself, I kinda/sorta miss the old name, but can see how it might not be entirely appropriate in these days of modern times. (Who knows, maybe T-47 will change the name back, just to flex his anti-woke chops.)

In any event, atmospheric rivers do a couple very important things, not the least of which is moving energy from the tropics to the mid-latitudes. They also bring water. A lot of water.

One of the most notable atmospheric rivers to hit northern California and the Pacific Northwest was just before Christmas in 1964. A couple weeks of heavy, wet snow had completely buried the region in mid-December; from the Sierra Nevada in the south, and north along the Cascades into Canada. This was followed by what was surely an AR5 event, which did two things over the course of a couple days just before Santa arrived: it dumped massive amounts of rain to be sure, but also melted the snow — fifteen feet of the white stuff at Crater Lake was turned back into the liquid phase, leading to a hundred-year flooding event.

Back in the 70s I was working on a copper project along the middle fork of the Eel River in northern California. The “Island Mountain” deposit was on the north bank of the river, but our access and camp were on the south. As such, we had to cross the Eel at least twice a day. One of the marvels of the trip was the ruins of a steel bridge on the floodplain — inch thick steel I-beams two feet wide, twisted like pretzels. During summer the crossing was no big deal, but the assay results were positive and the claim owner wanted to drill through the winter (which is also the wet season).

Our only access after the Eel flooded was to walk across the railroad bridge, through the seven-thousand-foot-long tunnel and then back up and over the mountain to the deposit. It was truly intimidating to stand on the bridge and realize that it had been completely washed out by the 1964 flood and the river had been running through the tunnel and out the northern end (and in doing so, also bypassing the bend in the river).

Projected rainfall and snow accumulations are always fraught with uncertainty: there are way too many variables to muck up the forecast. It’s the whole “A butterfly flaps its wings in China and we get snow instead of sun” scenario. Weathermen (and women) do their best, but it’s the nature of the job to be wrong more than they’re right. S.T.B.T.

The Weather Underground website, pictured above from this afternoon’s forecast, actually gives projected rainfall (and snow) totals along with their general predictions. From the screen dump for this week in Selma, it looks like we’re gonna get nearly a foot of rain by the weekend (and then more after that). So yeah, our typical fall is back and we’re gonna get wet. Could they be wrong? Of course! But even if they are off by half, it’s still a buttload of precipitation — we should probably start to practice treading water.

Under the assumption that they are at least somewhat close, Susie and I went into town this morning for a store/gas run (we beat the first bands of drizzle by about an hour). Also, assuming another of the all too regular power disruptions, I loaded up the deck with firewood, and filled the extra cans with gas for the generator — it’s not big enough to run the house (and a P.I.T.B. to hook up), but at least we won’t lose our refrigerated foods like we used to. Good news all around.