Los Angeles in extreme mega drought year vs. extreme mega wet El Niño Year... (climate, snow)

[AdriannaSmiling]

With the focus on realistic climate scenarios and the talk of a very strong El Niño possibly coming this summer or fall, I decided to create a thread about the city in the U.S. that would be most probably be affected by it; Los Angeles. Average rainfall in downtown LA is about 15 inches but in drought years, they've had years with less than 4 inches and during some very strong El Niño winters, they've had well over 30 inches for the rainfall years (measured from July 1-June 30). For references here are the norms:
Climate of the Los Angeles Basin - Wikipedia, the free encyclopedia

I created two hypothetical scenarios for downtown L.A; one being a super wet year in an extremely strong El Niño and the other being the most extreme form of drought possible.

I could only create one poll but if you find this thread of interest, please vote all of the following by responding to the thread:

A) Choose the one you'd personally like better.

B) Vote for the one that you think is more realistic to actually happen in L.A.

C) Explain which one that you think would cost the state more money in catastrophic loss (Remember that the both the LA area ecology and engineering are NOT build to withstand heavy rains so it doesn't take much too create mudslides, flooding etc). While 50 inches of rain does not sound like that much to people from wet climates, it would cause major damage and havoc in LA. OTOH, a drought so extreme that LA gets zero rain for a year would mean the whole state is experiencing a very severe drought which would mean all the reservoirs in the state as well as the snowpack in the mountains would run empty and the state would have cease all farming and pay premiums to import water from other regions just for day to day functioning. Lots of vegetation would die and the economy would falter.

[Ethereal]

Of course the dry one.

[AdriannaSmiling]

Me thinks both are extremely unlikely but totally possible and about equally so.

Interesting tidbit. Downtown L.A. has only had 1.76 inches of rainy from July 1st, 2013 through February 25, 2014 (despite December thru February being their so called rainy season). Today they are being slammed with a major storm (by California standards) that is forecast to bring 2-4 inches of rain in most parts around the L.A area so will receive more today than they have over the past 8 months cumulatively.

[snj90]

Oops, I voted for the first (the wet one) before noticing you were asking which was more likely. I was voting on the basis of preference, as 50 inches of precip is close to what we get.

[AdriannaSmiling]

Originally Posted by snj90

Oops, I voted for the first (the wet one) before noticing you were asking which was more likely. I was voting on the basis of preference, as 50 inches of precip is close to what we get.

Do you think the zero rain is more likely than 50 inches? I know L.A. is dry and getting less than an inch in a year is very possible scenario but for zero rainfall in an entire year, it would have to be a mega extreme version of the current drought.

[snj90]

Originally Posted by AdriannaSmiling

Do you think the zero rain is more likely than 50 inches? I know L.A. is dry and getting less than an inch in a year is very possible scenario but for zero rainfall in an entire year, it would have to be a mega extreme version of the current drought.

That's my line of thought on this. Zero (not rounded) is a difficult value to achieve. It can easily be much, much less likely than, say, 1 inch.

[wawa1992]

Less than an inch? More likely than 50.

NO rain at all? That means it never rained during a season, and that's exceptionally unlikely, probably about as likely as 200 inches of rain. In other words, once in several thousand years or more.

[AdriannaSmiling]

Originally Posted by wawa1992

Less than an inch? More likely than 50.

NO rain at all? That means it never rained during a season, and that's exceptionally unlikely, probably about as likely as 200 inches of rain. In other words, once in several thousand years or more.

ARE you aware how DRY LA can be even during the so called "rainy season"....L.A has recorded several TOTALLY rainless Januaries (including this past one) and Februaries even though those are their rainiest months. It can mimic that Atacama in extreme drought situations. OTOH, they have also recorded individual months like my 50 inch scenario in El Nino years but not cummulatively in one year. 2013 saw only about 3 inches of rain TOTAL for the ENTIRE year. Take away the few light rain events they got in 2013, and you have the mega drought year. OTOH, they got well over 4 inches of rain over a period of 3 days during a recent storm. Have a year with multiple events like they got in the recent storm and you have a year like the 50 inch scenario. They usually literally get no rain from May through September (like the Atacama desert dry where even a light rainfall is a once a decade event), but in my mega El Nino scenario, a named tropical storm makes landfall on the Southern California coast in August leading to a rare summer heavy rainfall. A tropical storm made landfall in Southern California in 1939 so if it happened once I'm sure it can happen again.

LA can have some desert years but no "true desert" would get years with over 30 inches of rain in it which is why it's classified as Mediterranean and not desert. IMO, your scenario of 200 inches of rain in a single year in LA is about as likely snow in Singapore or a thunderstorm with rain (not snow) at Vostok Station while the zero rainfall is still a possibility (even if remote). Just remember that the LA area has only been keeping records for about 150 years and we don't know what happened for the thousands of years before that. They probably had multiple years with zero rain (maybe even consecutive) at some point in the past 1000 years.