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May 23 2014

Why you shouldn’t try to defend your house against a wildfire with a garden hose.

Published by at 6:03 pm under Uncategorized

I live in an area where wildfires are part of nature. I am also an “early evacuator” – happy to get out of the way of any potential fire hazards if one is coming my way. I know that there are others who want to stay back and defend their homes, typically with a garden hose.

Here’s a photo sequence of the recent fires that proves my point. It shows an ember gaining a foothold on a hillside, which engulfs the whole hillside and creates a 100′ tall fire tornado within 15 minutes.

Jeff Anderson, Elfin Forest Recreational Reserve park ranger, took these remarkable images during the recent “Cocos Fire” in North San Diego County.  The fire started quickly in the late afternoon of May 14. The next morning (May 15), it seemed to be fairly tame until about noon.  Then it flared up with a vengeance.  My home was about 1000 feet downwind of the evacuation zone, and we could smell the smoke passing over us, so we were intensely focused on what was happening.

Jeff was on the ridge of the Elfin Forest reserve looking north towards Harmony Grove when he snapped this photo of an ember burning at 12:25:24pm on May 15:

Fire 5-14_254

Just two minutes later, at 12:27:30pm, the fire from the original ember fire spread considerably, and another ember jumped up the hill:

Fire 5-14_256

Four and a Half minutes later, at 12:32:07, the fire engulfed the whole side of the hill. At this point, the flames were probably burning 1200 – 1600 degrees F.

Fire 5-14_262

Eight minutes, later, at 12:40:05, the fire had generated a “fire tornado” about 100 feet high, with winds 50-80 mph. The temperature at the base of the tornado was probably about 2000 degrees F, about one fifth the temperature of the surface of the sun, and the fire was generating its own wind:

Fire 5-14_275

I would ask those who would try to defend their house by playing Rambo with a garden hose, how long they think they would last in the midst of that inferno. It’s not a matter of your skill or machismo, it’s simply a recognition of the overwhelming power of nature.

We also need to recognize that wildfires are a natural part of the ecosystem. We even have a flower, the Fire Poppy, that germinates after wildfires. Here is picture I took of a fire poppy at Lake Poway, six months after the area had been burned in the 2007 Witch Creek Fire:

Fire Poppy

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Images by Tom Munnecke is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States License.
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