Los Angeles On Track For Driest Year Ever - 2.4" So Far In Water Year 2007 - LA Times

[hatrack]

Put away that umbrella and hold on to that moisturizer. The National Weather Service on Monday declared that Los Angeles is experiencing its driest year on record. Only about 2.40 inches of rain has fallen on downtown Los Angeles since July 1, and there's no sign of rain through at least the middle of this month.

Forecasters expected February — historically Los Angeles' wettest month — to provide some relief, but it didn't. Now, the National Oceanic and Atmospheric Administration's weather models suggest that a La Niña climate pattern is emerging in the Pacific, continuing the drought-like conditions.

The prolonged dry spell contributed to an unusually long fire season, rife with Santa Ana winds that have extended into March. The last time it was remotely this dry was 1924, when 2.50 inches of rain had fallen. "We've never had a drier year on record so far," said Eric Boldt, a meteorologist with the National Weather Service in Oxnard. "If nothing significant happens in March, then we've pretty much run out of time."

Only two years ago, Southern California's rainfall was posed to set an all-time record. In the end, 2005 turned out to be only the second-wettest, but the precipitation helped the area avoid more severe drought conditions this year. Local aquifers were filled to the rim in 2005, so water supplies generally are solid. Heavy snow in the Sierra Nevada — another key source of local water — has also helped. California's reservoirs are actually running above normal this year. Pyramid Lake and Diamond Valley Lake — two major local reservoirs — are at more than 90% of capacity.

EDIT

http://www.latimes.com/news/local/la-me-dry6mar06,1,5235953.story

[kestrel91316]

1. We're still having warm, extremely dry winds here recently. Only

a few token light rains over the past few months................

It was hot yesterday, too - in the 80s. My office got REALLY uncomfortably warm and I almost had to turn the AC on.

[necso]

2. For those of you unfamiliar

with SoCal, there are two types of drought that we're concerned with here: local drought, which increases fire danger, is hard on the local flora (for example, various parasites (eg, bark beetles) and diseases can really ravage the trees when these are drought-weakened) and fauna, etc; and drought where we (principally) get our water from.

And to understand how important location is (storms typically come out of the northwest, and the further south you are, the less rain (precipitation*) generally makes it to you from these types of storms**), check out these numbers for annual rainfall:
Los Angeles: 14.77 inches;
San Diego: 9.46 inches.
(Both numbers are from NOAA; these numbers vary depending on which years are included, but they are adequate here.)

If we don't get the normal precipitation during the "rainy" season, then we must look for certain other things to mitigate the fire-danger (and specifically to push the peak fire-danger towards cooler, or at least shorter, days):
* a strong marine layer during the spring months (whenever possible) to keep humidities high (and temperatures down);
* moderate temperatures;
* low winds; and
* summer "monsoonal" rains (a thin reed generally).

If all these things should fail us, and as the rains of two years ago resulted in much growth of grass, brush, etc -- and as the flora is already showing signs of drought-stress -- fire season could be a bear.

*: Local geography is also important, but that's a too-lengthy discussion.

**: There are a number of different patterns for storms, and these patterns affect how much precipitation can be expected out of a storm, particularly when local geography is considered. For example, the last storm (westerly, in microcosm) got "caught up" on the mountain and gave us a fair amount of precipitation, more than otherwise would've been expected. Similarly, summer monsoonal rains often never make it (west) over the ridgeline. (The rain-shadow works both ways.)

[phantom power]

3. It's the water-budget kind of drought that's really going to fuck us.

Losing the winter snow-pack in the Rockies and other southwest mountain ranges. It's going to cream us, and hardly anybody is even paying attention.

[NickB79]

4. How is the snowpack in the Rockies this winter?

Are we below average again?

[phantom power]

5. To my knowledge, yes. I know that here in AZ...

the CO-plateau snowpack was very low for the nth year in a row. The hydrologists are predicting a "bad water year." The general trend seems completely unstoppable to me. The world is getting warmer. I cannot conceive of a scenario where that leads to anything but less and less snowpack, and therefore to less and less water each summer.

And that is why I now hope for a Younger Dryas ice-age.

[XemaSab]

8. I think we have no *clue* what's going to happen when that switch flips

Could hurricanes hit LA? Why not?

What about other sources of Summer moisture, like the monsoons? That would really throw everything for a loop.

Or what if there was a permanant high pressure system over the area caused by the northward movement of the Walker and Feral cells?

Good times. :D

[depakid]

10. Very little of the monsoon hits LA

It pretty well stays in Souther Arizona, although occasionally there'll be a couple of thunderstorm in July- but they don't produce much measurable rain.

I have a bad feeling about So Cal this year.... I think it's going to get extraordinarily hot really burn again.

[XemaSab]

11. Very little of it hits LA now

But why not more in the future?

Or just a few good lightning storms in the middle of August with no precipitation? :shrug:

[necso]

7. Another interesting thing about SoCal

is that we import water both from the Colorado and from up north (exact proportions vary, therefore which "basin" is of most concern to a user also varies; my water is local groundwater), so we have multiple drought conditions to be thought about within this concern.

However, the potential for devastating fires is a more pressing concern for me personally. And long-day fires (other things being equal) are of greatest concern to me here (local circumstances are very important); the only time that the immediate-area was evacuated (since I moved here) was shortly before the Fourth of July some years ago. (I sat on Little Thomas Mountain -- there's a nice sitting-stone there, most appropriately placed -- and watched the fires and the aircraft fighting them; there was also a fire on Cahuilla Mountain. We're much better prepared now -- flight is not our plan.)

[Solo_in_MD]

6. And what is DWP doing about it

- New homes continue to be built
- Golf courses continue to be watered

They will attempt to back out of agreements on the Owens Valley and steal more than their fair share from the Imperial Valley and Colorado river.

The LA area needs to take a serious look at its water use and take some drastic measures.

[XemaSab]

9. The whole flippin' western US needs to take a look at water

They are still building golf courses in Palm Springs, Santa Barbara, and other areas where there are chronic water shortages.

Golf sucks.