Record Rainfall in my Little Town

It's been a rainy night. At 1:00PM this afternoon, I've recorded 2.05 inches from a storm that began yesterday evening. Added to the 0.48 inches a few weeks back, we've had 2.53 inches in the month of October. This is 0.01 inches short of the record for the month in my data that goes back to 1991. And we have one more powerful storm due to arrive Sunday (during my scheduled field trip, of course...). We will break the record for October.

Source: NWS Sacramento

This would seem like great news in regards to the drought that has afflicted California since 2011, but such thinking would most definitely be premature. As one can see in the flooding advisory above, the most intense part of this storm is centered right over our area, and other areas may not be receiving as much precipitation. In addition, this storm may not reflect a changed pattern. At least some of the additional moisture was captured from the remnants of a tropical storm, and that sort of thing won't be happening as the winter intensifies. Long range forecasts are not particularly promising for Southern California and the Southwest (below).

Still, there has been rain across the state this week, and I'd rather see rain falling rather than continued dry conditions. It's a start when you can have a fifth of a year's normal rainfall in the bank before November arrives.

Rainfall milestone this week in my corner of California

We reached a milestone this week in my backyard (backyard in both the literal and figurative sense). We reached "normal". I've been tracking rainfall totals in my backyard since 1991, and up until 2011, the average yearly rainfall has been 14.67 inches per year. The last four years of drought brought the average down to 13.92 inches, but the last nine days have brought us 2.98 inches of rain, and the year's total now stands at 14.51. It's the first time we've reached "normal" in five horrible dry years. Another storm will barrel through the area on Sunday.

There were great hopes that the El Nino event, the strongest ever recorded, would have brought us far more than normal rainfall, but that is seeming more and more unlikely. I'll take normal any day, though, and the region around is reaping a bounty of moisture. It will be a banner year for wildflowers in the canyons and foothills of the Sierra Nevada, and the prairies around my home are already colorful in places. Death Valley has experienced a rare "superbloom", which I was privileged to witness (pictures coming soon).

A very dry (and very warm) February raised the specter of an early melting of the snowpack in the high country, with only one significant storm. A similar situation last year left us with 5% of normal snow in April. We had dropped from a surplus of 110-plus percent to something like 80 % of normal. The March storms dropped five feet or more of snow in many parts of the High Sierra and Cascades, so there's good news in the high mountains too.

Is the drought over? Not by a long shot. The rain and snow are significant, but the groundwater and soil conditions will take a long time (if ever) to recover. The reservoirs of California, with just one exception, are still well below normal. Some reservoirs have a decent chance of filling this year, but there is a long way to go before we can make up the deficit of the last five years. One of the problems is that a reasonably wet year can cause consumers to relax their efforts to conserve, and one of the real problems of our state is that even a normal year no longer provides enough water to meet all the demands. A political conversation needs to happen about our way forward. With global warming, droughts may very well become more frequent, and a return of "megadroughts" lasting decades are a possibility (two megadroughts in the last 2,000 years lasted upwards of a century each).

http://cdec.water.ca.gov/cgi-progs/iodir/B120UP

The Rains Come and the Snow Falls: Normal in California Doesn't Feel Normal

Normal just doesn't feel normal.

In 2014, researchers were declaring the California drought the worst in 1,000 years. And then we had a year, 2015, that was in many ways much worse. We actually had near normal rainfall on the valley floor that year, but it was so warm that the snowpack ended up at 10% of normal, a value never recorded previously. It has been a horrific time. Not only are the reservoirs low and agricultural fields dying away, groundwater has been overdrafted at catastrophic rates, and the worst wildfires in living memory have destroyed vast swaths of forests in the Sierra Nevada and Southern California.

Dry Creek, January 20, 2016

It's not going to get all that much better. Climate models are suggesting that megadroughts, lasting decades, will be the norm starting in about 30-40 years. So this year has been one of hope, in California anyway. El Nino, the climate phenomena that causes all kinds of chaos across the world, tends to bring lots of rain to California (it also unfortunately brings drought elsewhere).

The storms so far have actually not been directly related to El Nino. They have been cold arctic storms that have been dropping prodigious amounts of snow in the Sierra Nevada. For the first time in five years, the snowfall has been above normal. Not far above normal, around 110-115%, but it feels unprecedented after such a long period of paltry precipitation.

The climate of the floor of the Great Valley is semi-arid to desert. The winter rains don't contribute much to the agricultural yields, but wet years are important, as they allow for some recharge of the groundwater. It's never been enough, so our groundwater "savings account" is always shrinking overall.

So I've been watching the precipitation pretty carefully of late. Well, actually I've been tracking rainfall amounts in my backyard rain gauge since 1991, and this year has been interesting. At 2.82 inches, the November rain was the second highest I've recorded. December didn't set records, but 2.60 inches fell that month. But once January arrived, the spigots opened up, and we've four good storms already, dropping 4.21 inches. We've already reached 10.01 inches for the year, where 12 inches is average for an entire season.

Dry Creek on January 7, 2016

Two weeks ago, I noted that Dry Creek, a minor tributary to the Tuolumne River, was "flooding". The earlier storms had only been percolating into the dry soils upstream, but the first heavy storm in January ran off, producing a flow in excess of 1,000 cubic feet per second. We got two more inches of rain in the last three days, and Dry Creek was flowing at nearly 3,000 cubic feet per second this morning. It was a delightful sight.

Dry Creek in March 2011, at more than 3,000 cfs

The future is hard to predict. Last year, we had a wet autumn, but there wasn't a single drop of rain in January, and what little snow had fallen quickly melted away. According to the climate models, the El Nino storms will be starting to affect California in a matter of weeks, bring intense warm storms, primarily to Central or Southern California. There can be no doubt that we need to fill our depleted reservoirs, if for no other reason than to stop depending on groundwater during the irrigation season.

Merced National Wildlife Refuge, January 2014

But I also worry about the health of our regional wild habitats. The wildlife refuges of the Great Valley are critical roosting places for millions of migratory birds, and they tend to be at the low end of priority for water allocations. The rivers that I love, the Merced, the Tuolumne, and the Stanislaus, have been running low and warm, killing tremendous numbers of native fish, and allowing the spread of invasive Water Hyacinth. We've taken over 95% of the natural habitats of our valley, and have a responsibility for taking care of what little remains.

It's been normal, but it doesn't feel normal.

A Scary Story for Halloween: Rainfall Totals in My Neck of the Woods

It's Halloween night, and a lot of children are no doubt disappointed that it is raining outside. We've had four kids in one group so far. Waiting for trick-or-treaters this evening has been a little like waiting for rainstorms in California over the last three years.

I love numbers and statistics. I've lived in the same location for the last 23 years and the first year I was there I got a nice rain gauge for Christmas. I've been using it to keep track of precipitation in my Great Valley town about 13 miles east of Modesto. We are roughly at the middle of the valley (the center of the Central Valley!), about 200 miles north of Bakersfield, and about the same distance south of Redding. The valley climate ranges from Mediterranean in the north to desert in the south (Redding averages about 34 inches of rain per year while Bakersfield averages just over 6 inches). Modesto's 108 year average is 12.15 inches. The highest recorded rainfall was 26.01 inches in 1983 with the lowest at 4.3 inches in 1913.

I now have nearly a quarter of a century of rainfall records from my backyard, so I thought I would make some comparisons with our nearby city. The average yearly rainfall in nearby Modesto since  1991 has been 13.04 inches per year, an inch higher than the long-term average. In my little town the average from 1991 to 2011 was 14.55 inches, with a high of 26.42 inches in 1998. Waterford has had higher rainfall than Modesto in 20 of the 23 years that I've measured. I am guessing this is because we are slightly higher in elevation (by a grand total of 70 feet or so), closer to the Sierra Nevada foothills, and farther from the rain shadow of the Coast Ranges.

The most rainfall I recorded in a single day was 2.32 inches on January 2, 2006, and the wettest single month was February of 1998 with 8.64 inches. Some of you in wetter climates may find these numbers amusing (I note a day in 2010 when Big Sur got 22 inches of rain...in 24 hours!). But as I've said, we live in an arid climate.  Irrigation is all that keeps most parts of it green.

The scary part of the story is that of the last decade. There were a few wet years, but six of the last eight years have been well below average, only about 75% of what was once normal. Last year was the driest I've recorded. Our reservoirs are functionally empty and there has been little or no snowpack. We actually drove over Tioga Pass in January of 2012, and it was t-shirt weather. Tioga is usually closed from November to May because of snow, but not these days.

Here's hoping that tonight's storm, as disappointing as it is for the Halloween trick-or-treaters, is a harbinger of wetter times to come. It's a frightening situation all around.