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Thursday, February 13, 2025

So it's been raining…


Visitor submit from Tom right now. Elizabeth is spending a while in Georgia tending to our youthful youngster, who was struck crossing the road by a pickup truck that ran a pink gentle (after which proceeded to hurry off). Whereas our youngster has suffered a number of damaged bones, and will likely be confined to a wheelchair for a number of months, we have now each expectation of a full restoration.

As you’ve in all probability heard, we’ve been getting plenty of rain in California lately, as weeks of atmospheric rivers hit the state in late December and early January. We’re okay right here – a little bit water within the storage within the nook that all the time will get a little bit water – nevertheless it’s been plenty of rain suddenly, and we’ve seen impacts each regionally and statewide. Regardless of some drizzle right now, the final week has been dry, cool, and clear, and it’s alternative to evaluate the place we’re and the place we’re going.

To speak about the place we’re, let’s begin with the place we’re geographically, which in line with FEMA is in a particular flood hazard space. Right here’s a close-up of the FEMA flood map for our neighborhood:

Excerpt of a FEMA Flood Map

Poppy Corners is positioned towards the underside of that picture, firmly within the blue-colored area that represents the realm that has a 1% annual probability of flooding (Zone AE in FEMA-speak). Due to our location on this map, we’ve needed to pay flood insurance coverage as a situation of our mortgage, which units us again a tidy sum annually – rather more than our common house owner’s insurance coverage. Most years, and definitely within the current drought years, it has appeared absurd that we have now to pay flood insurance coverage, however right here we’re.

On the prime of the map you see the rationale why our neighborhood is in Zone AE – the Sans Crainte creek. Within the time we’ve lived right here, the creek has been aptly named (Sans Crainte in French means “With out Concern”). Many of the 12 months, this creek is totally dry, and whereas we’ve seen water in it often when it rains, and listen to some peeping frogs now and again, we’ve not been scared of that creek.

Then we bought plenty of rain on New 12 months’s Eve, and that is what occurred:

For those who look intently on the FEMA map, you’ll see a marking the place the creek goes right into a culvert below the roadway. On New 12 months’s Eve, there was sufficient water coming down the creek that it exceeded the capability of the culvert, and so the water got here down our avenue, to the 2 storm drains for the entire neighborhood which are proper in entrance of our home. We, and all of our neighbors, took a eager curiosity in guaranteeing these storm drains remained clear. In our 18 years of residing right here we’d seen fairly a little bit of storm water, however nothing like what we noticed that day.

A fast mathematical diversion: As I discussed, the blue zone on the FEMA map corresponds to an space that has a 1% probability of flooding – the so-called 100-year flood. What’s essential to recollect is that that’s the prospect of a flood each given 12 months. Our possibilities of not flooding in any given 12 months are, subsequently, 99% (simple sufficient), however factor get trickier after we’re calculating the percentages of no floods for a stretch of time. The possibilities of no floods two years working are 99% instances 99%, or 98%. 5 years working involves 99% x 99% x 99% x 99% x 99%, which works out to 95%. Multiply it out for our 18 years right here and now the possibilities of being flood-free that entire time are right down to 83.4%. Odds of no floods over a 30-year mortgage? 74%, or (put otherwise), there’s a 1-in-4 probability that you simply will get a flood throughout that 30-year timeframe. That’s not horrible odds, nevertheless it’s not nice both.

So the place are we traditionally with all this rain? Because of the climate station I bought us for our twentieth wedding ceremony anniversary (twentieth is climate station, proper?), we’ve bought a couple of 12 months’s price of native rainfall knowledge. The California Division of Water Sources defines our “water 12 months” as working October 1 – September thirtieth, and based mostly on our climate station, in simply 4 months of the 2022-23 water 12 months we’ve gotten over 20 inches of rain — greater than the 16 inches we bought in 2021-22, and almost tripled the 7.5 inches in 2020-21 complete. Right here’s a graph:

You possibly can see why we outline our water years as working October – September, versus January – December – we’ve bought this lengthy dry stretch for almost half the 12 months, after which issues begin choosing up in October. This graph additionally reveals a part of the issue that we have now in California – a minimum of in recent times, after we get rain we get plenty of it suddenly, after which nothing.

For an extended historic context, I turned to the publicly-available and downloadable native climate info from the Nationwide Oceanographic and Atmospheric Administration’s Nationwide Facilities for Environmental Data. Their Local weather Information On-line service permits you to obtain climate knowledge taken by native entities. Your mileage could differ — totally different climate stations could measure simply temperature, or have info for only a few years, however with a little bit poking round I used to be capable of get rainfall figures from Buchanan Discipline, a small airport only a few miles north of us, for over 20 years of knowledge – from the 1999-2000 water 12 months to current. Their rainfall totals are constantly a little bit decrease than our climate station’s – probably reflecting barely totally different climates; additionally probably reflecting the truth that our climate station is a client product. Right here’s a graph:

The common annual rainfall at this climate station is slightly below 15 inches, and this 12 months’s complete up to now is at that common. Solely time will inform whether or not we’ll get extra rain this 12 months, or if it will wind up simply being a mean 12 months.

This graph additionally helps to inform the story of the current drought – how we’re coming into this 12 months having three years working of below-average rainfall quantities, and the way the 2020-21 water 12 months was the driest on this 20-year time interval.

That then leads us to the massive query with all this rain – the place are we in relation to California’s ongoing struggles with drought? All this rain has had a optimistic impression on drought circumstances all through the state, however drought circumstances persist. Right here’s a side-by-side comparability of statewide drought circumstances originally of this water 12 months and now:

The U.S. Drought Monitor is collectively produced by the Nationwide Drought Mitigation Heart on the College of Nebraska-Lincoln, america Division of Agriculture, and the Nationwide Oceanic and Atmospheric Administration. Map courtesy of NDMC.

Issues are considerably higher than they had been again in October, when 40% of the state was in “Excessive” or “Distinctive” drought. Proper now, there aren’t any areas of the state in these zones. That stated, even with all this rain, drought persists – solely 0.64% of the state is in “no drought” circumstances, that tiny little nook within the northwest of the state.

This are additionally wanting higher in California reservoirs. Practically all of them began the water 12 months with ranges profoundly beneath historic averages – the mighty Shasta Lake was at 60% of historic, and near our coronary heart Lake Oroville was at 64%. As of this week, Shasta’s as much as 87% of historic, and Oroville’s at 111%.

California Division of Water Sources

Nonetheless an advanced image, and we’ll need to see how the snow pack shapes up this 12 months, however higher.

As a ultimate “the place are we?”, we’re undoubtedly in a spot the place we have now to attempt to get out and benefit from the water within the creeks that so typically we discover dry. It may be difficult to seek out good mountain climbing circumstances, hanging a steadiness between having fun with working water and getting caught within the mud, however there are additionally distinctive alternatives to check one’s skills to ford streams and see simply how waterproof these boots are. Right here’s a couple of stream crossings from a current hike.

Hope y’all are staying heat and dry wherever you’re!

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