The approaching El Niño weather has drawn attention from the federal down to the local level. In September, the local Mountain Disaster Preparedness group held a meeting that attracted more than 100 people to hear about the forecast of a wet winter.
Riverside County has initiated plans. All fall, Cal Trans and the county Transportation Department have been clearing culverts and scraping berms along roadsides to prevent flooding and pooling of run-off. Last week, the county Emergency Management Department held a meeting at the Nature Center. Besides discussing plans, actions and preparedness, the agency distributed bags for sand.
On Wednesday, Dec. 9, the Federal Emergency Management Agency held a drill and press conference to announce the work it has begun to prepare for possible significant disasters from inundating rains.
Among FEMA’s actions was preparing its Severe El Niño Disaster Response plan. The El Niño task force focused on interpreting data in areas of California, Arizona and Nevada (FEMA’s Region 9), which have proved historically vulnerable to heavy and prolonged rains. Through this assessment, the task force seeks to identify critical decision points during all phases of a potential incident — from pre-incident, incident onset, to response and recovery.
The latest National Weather Service forecast for this winter, released last week, states, “El Niño is expected to remain strong through Northern Hemisphere winter 2015-16, with a transition to ENSO-neutral anticipated during the late spring or early summer 2016.”
The FEMA report identified several important aspects of a strong El Niño pattern. Not only are there more wet days, but the wet days tend to be wetter than a normal rainy winter day. Looking at records from the 1997-98 El Niño, several California communities experienced rain on 25 or more days in both January and February.
“The lack of any significant letup in rains allowed almost no days for drying,” the report’s authors wrote. “Each period of heavy rain sent more earth sliding to lower elevations at a number of locations in the central and south part of the state.”
“Understand the risk of where you live and where are the flood areas,” advised Robert Fenton, the FEMA Region 9 administrator. “Have a plan; know where to go during and after the storm.”
This would include extra batteries, a radio, flashlights and potable water. He recommended individuals purchase flood insurance. Already this fall, more than 7,100 new policies have been issued.
But FEMA did identify a slight silver lining in the four-year drought: “There is a reduced expectation for main-stem river flooding compared to previous El Niño seasons. This is mainly attributed to the drought and current reservoir capacity to store more water.”
Because of the drought, storage basins are much lower than in 1997-98, thus they have more capacity to store water as streams and rivers flow into the storage areas. For example, in 1997, Lake Perris was at 81 percent of its capacity. In October 2015, it was at 36 percent of capacity.
However, the severity of the drought has hardened soils, and during and after the first rains, soil may “act like cement, making it difficult to soak up rains increasing run off … From a meteorology standpoint, this is the greater concern for flooding for this upcoming season,” according to the report.
Todd Morris of the National Weather Service advised, “The current El Niño has reached the strong category … This one is very similar to the 1997 El Niño, at least to its strength and may exceed it within 30 days … The impacts will be seen mainly in January through March and it has the potential for one of the strongest El Niños in history.”
Mark Ghilarducci, director of California’s Office of Emergency Service, said besides flooding, residents should be aware of areas where soils and rocks could move and slide, such as the Mountain Fire burned areas. “Debris could tumble down with little warning,” he said. “We want to empower the public with as much information as possible.”