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dauben
Citruholic
Joined: 25 Nov 2006
Posts: 963
Location: Ramona, CA, Zone 9A
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JoeReal
Site Admin
Joined: 16 Nov 2005
Posts: 4726
Location: Davis, California
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| Posted: Fri 15 Feb, 2008 6:42 pm |
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Oh man, that's worse that I thought. It cleaned everything out, including dauben's posted message!
.... sorry, couldn't resist.
I hope you guys are okay down there. |
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dauben
Citruholic
Joined: 25 Nov 2006
Posts: 963
Location: Ramona, CA, Zone 9A
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| Posted: Fri 15 Feb, 2008 6:45 pm |
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| JoeReal wrote: | Oh man, that's worse that I thought. It cleaned everything out, including dauben's posted message!
.... sorry, couldn't resist.
I hope you guys are okay down there. |
For some reason it won't let me post the URL's of the citrus groves under water. Everything is just blank. You guys must not be using your secret decoder pens. 
Phillip |
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dauben
Citruholic
Joined: 25 Nov 2006
Posts: 963
Location: Ramona, CA, Zone 9A
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| Posted: Fri 15 Feb, 2008 6:46 pm |
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Skeeter
Moderator
Joined: 23 Jul 2006
Posts: 2218
Location: Pensacola, FL zone 9
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| Posted: Fri 15 Feb, 2008 10:27 pm |
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Amazing that less than 1 inch of rain can cause flooding there-- anything less than an inch here is just a shower. We frequently get rains that produce 4 to 6 inches and record rains are in the 25 to 40 inch category (those cause flooding here).
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Skeet
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Millet
Citruholic
Joined: 13 Nov 2005
Posts: 6656
Location: Colorado
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| Posted: Sat 16 Feb, 2008 2:08 am |
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Skeet, that was my very first thought, when I seen the pictures, and read the information. I never heard of such a small amount of rain ever causing any trouble. - Millet |
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dauben
Citruholic
Joined: 25 Nov 2006
Posts: 963
Location: Ramona, CA, Zone 9A
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| Posted: Sat 16 Feb, 2008 4:33 am |
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| Skeeter wrote: | | Amazing that less than 1 inch of rain can cause flooding there-- anything less than an inch here is just a shower. We frequently get rains that produce 4 to 6 inches and record rains are in the 25 to 40 inch category (those cause flooding here). |
Welcome to San Diego . . . 0.1 inches in one area and 3 inches in others. Typically, the coastal areas get a lot less rain than inland does. There are also a number of factors that cause flooding other than precipitation total. Factors such as soil type (imperviousness), antecedent moisture conditions (ie how wet the soil is from previous storms), time of concentration (Rain on slopes of 30% runs off much faster than flat land), and rainfall intensity (1" per hour vs 1" per day).
The area where I believe those citrus pictures were taken is a good example. The trees are down in a valley surrounded by a lot of steep mountains with a lot of rock (low imperviousness). The rain dumped a lot of water in a short period of time. What little soil there was has been saturated from previous storms. The rainfall quickly traveled down the mountain and hit the valley. To make problems worse, the flatter terrain of the valley doesn't convey water out as fast is it was coming in. In the end, they shut down the freeway in and out of the area I work in due to flooding, but probably more because of the mudslides from the burned out areas.
What's funny is I met with FEMA again today and they said that they haven't closed the October fire "event". Technically the fire event is still occuring because they are keeping it open due to the damage from debris flows, erosion, and mudslides indirectly caused by the fire
Anyway, if anyone's interested in the rainfall patterns in San Diego, you can see how much it varies within the County from the 85th Percentile Isopluvials maps at the link below. You can see that some areas get three times as much rain as others.
http://www.co.san-diego.ca.us/dpw/docs/pct85.pdf
Phillip |
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Skeeter
Moderator
Joined: 23 Jul 2006
Posts: 2218
Location: Pensacola, FL zone 9
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| Posted: Sat 16 Feb, 2008 9:20 pm |
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Amazing that you can even keep cactus alive with that kind of rainfall. We get over 5 ft a yr. When I was a teen, I remember Mobile, AL getting over 7 ft. It is not uncommon to get 12 inches in less than 12 hrs-- and that is just frontal rains or thunderstorms. Hurricanes can dump even more--we had one less than 10 years ago that dumped over 4 inches per hour for more than 4 hrs-- several entire watersheds got over 25 inches in 24 hrs.
I figured that soil and terrain had a lot to do with it to cause flooding with that little rain. Our terrain here is pretty flat-- the highest elevation within 50 miles is probably less than 300 ft and many areas are so sandy that even a 4-5 inch rain won't leave standing water in a flat field.
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Skeet
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dauben
Citruholic
Joined: 25 Nov 2006
Posts: 963
Location: Ramona, CA, Zone 9A
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| Posted: Sat 16 Feb, 2008 10:12 pm |
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| Skeeter wrote: | | Our terrain here is pretty flat-- the highest elevation within 50 miles is probably less than 300 ft and many areas are so sandy that even a 4-5 inch rain won't leave standing water in a flat field. |
The one good thing about San Diego is that we have just about every landscape within an hour drive (except for rainforest). We have ocean to the west, inland valleys, mountains, and desert; each with it's own climate. You mentioned 300 feet elevation change in 50 miles. My daily commute is over 1000-feet in elevation difference. In other words, I go 50 mph uphill to get to work and 75 mph downhill to get home.
Phillip |
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Skeeter
Moderator
Joined: 23 Jul 2006
Posts: 2218
Location: Pensacola, FL zone 9
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| Posted: Sat 16 Feb, 2008 11:49 pm |
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Pretty much a days drive to anything other than woods, beaches or swamps--though some would say we are close to a coastal desert even with all of our rain. There are many areas just inland from the beach where the vegetation is cactus, palmettos and scrub brush due to the lack of water holding capacity in the sandy soil.
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Skeet
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