With more rain on the way, officials warned Sunday about a growing risk of landslides in the burned areas of Los Angeles County, with a probability of 10% to 20% of significant sudden floods and debris flows capable of damaging roads and homes inside and around the areas devastated by forest fires.
“This is the worst case for which we must prepare,” said Kristan Lund, a meteorologist of the National Meteorological Service in Oxnard.
“We are increasingly concerned about the scars of burns,” Lund said. The carbonized footprint of the Fire of Eaton, which blacked more than 14,000 acres, is the most worrying. “These sudden floods and these rubble flows could occur inside, near or under these burns scars.”
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An flood alert entered into force at 10 am on Sunday and will continue until 4 pm on Monday for the areas burned by the Eaton fire in the areas of Altadena and Pasadena; Palisades and Franklin fires in the areas of Pacific Palisades and Malibu; the Hughes fire around Lake Castaic; and the bridge fire in the mountains of San Gabriel to the west and southwest of Wrightwood. The flood alert began six hours earlier than originally planned.
“The greatest risk of debris flows would be after 4 pm on Sunday,” said the weather service.
If you are not sure to be close enough of the burn scar, “assume it is,” Lund said. However, a city like Montebello, approximately 10 miles away from the area burned by the Eaton fire, is not considered close.
(National Meteorological Service)
“If you are close to the fire, you must be prepared,” Lund said. The measures that people can take are to avoid being in the area or its surroundings from Sunday afternoon until Monday afternoon; Use sandmand to protect property; And, for people who decide to stay, to supply supplies in case the road access is blocked.
A “landslide” is a term that covers everything and can describe any movement of rock, earth or debris downhill. A “debris flow” can occur when water flows quickly downhill and, in addition to mud, collects rocks, branches and sometimes huge rolled songs. This is also considered a type of slope landslide, which can occur with a potentially deadly force.
Animated infographic that shows the works of a debris flow.
Earth landslides are a risk after forest fires because the heat of fire makes the soil repellent to water. When the intensity of rainfall is high (they fall more than half inch per hour), the water can begin to flow down the surface downhill, instead of filtering underground, and can start collecting rocks and rubble.
“It really has to do with the trajectory of the storm,” Lund said. “They are the greatest potential for important rubble flows. They are the most recent burns scars; They are close to communities or vulnerable infrastructure. ”
The guidance of the land is also vulnerable in this particular storm. The scars of the burns are on the slopes of the mountains that look south, and the humidity of the storm is being attracted from the south, meteorologists say.
These factors could cause “more intense rains in those areas,” Lund said.
Forty rain totals for the three -day storm continue to increase. Until Monday, Covina could receive 1.32 inches of rain; The center of Los Angeles, 1.14 inches; Long beach, 1.12 inches; Canoaga Park, 1.05 inches; Santa Clarita, 1.04 inches; Fillmore, 1.02 inches; Redondo Beach, 0.95 inches; and Thousand Oaks, 0.87 inches.
(National Meteorological Service)
In addition to the risk of debris flow, there is the possibility of sea thrombas on the ocean, as well as harmful winds and strong thunderstorms, Lund said.
And more intense rains can still occur even if lightning is not seen or thunder is heard. But if you listen or see a storm, “you will probably have higher rain rates,” Lund said.
There are between 15% and 25% possibilities that thunderstorms are developed in a strip in southern California that includes recently burned areas, said Carol Smith, a meteorological service meteorologist. The storms could generate a probability of half -inch rainfall per hour to three quarters per hour in isolated areas.
Rain rates that exceed half inch per hour can cause debris flow in burned areas.
Smith said that the area burned by the Palisades fire could receive more than one inch of rain; The area burned by the Eaton fire could reach up to 2 inches.
(National Meteorological Service)
A slight rain began to fall throughout the region on Saturday night.
The storm will bring the first important rains of the year. Much of the south of California is in a “severe drought” and some areas in the southernmost part of the state are in an “extreme drought”, according to the US Drouckt Monitor.
The authorities advised the residents in the burned areas to use sandbags to direct the runoff and protect the property, clear the drainage paths, pay attention to the evacuation orders and stay away from the roads covered with rubble. They also said that residents should keep the garbage cans and vehicles outside the street to allow rainwater to travel freely and avoid contact with contaminated runoff.
“If emergency officials say that a certain area is avoided, do it,” said Smith.
