Flash Flooding and Flooding in California, August 31, 1998

Strong thunderstorms fed by intense heat and humidity under strong high pressure aloft, developed as an upper-level low over southern Nevada began drifting toward southern California. A few thunderstorms reached coastal areas, but most of the flooding and high winds remained farther inland. Flooding was widespread throughout the Victor Valley where 1 to 2 inches of rain was reported. In Hesperia, water was running 1/2 foot deep over some roads, flooding homes and intersections. Running water trapped several people in Lucerne Valley. In the mountains, street flooding was reported in Big Bear City, and in Forest Falls, Valley of the Falls drive was washed out. Strong winds blew down trees in Rialto, where a child was pinned against a car. In Moreno Valley, toppled power poles trapped one woman in her car for a time and several thousand lost power. In northern sections of San Diego County, gusty winds blew down hundreds of trees, including the 100 year-old "Bicentennial Tree" in Vista, and unroofed one trailer home in San Marcos. At the height of the storm, 45,000 homes and businesses were without power due to lightning strikes and downed power lines. Perhaps the hardest hit area was Hemet, where scores of massive trees were uprooted or torn apart, shingles blown off roofs, and fences toppled. Water was running over a foot deep through the streets and actually flowed through the Hemet high school gymnasium. The combination of wind-blown power lines and lightning, sparked numerous grass and brush fires. In Yucaipa, a 30 acre blaze threatened several homes and forced the closure of Highway 38 before rain and fire fighters brought it under control. In Ramona, about 4800 acres were charred, and hundreds of people evacuated as well. A much more destructive wildfire developed from several lightning strikes and strong winds in the Juniper Flats area. This fire went on to burn some 6000 acres, and destroyed 44 residences, 46 other structures, and 98 vehicles. The total loss from this wildfire alone was estimated at $4.45 million. Farther west in Orange County, a thunderstorm funnelled winds estimated at between 60 and 70 mph through Trabuco Canyon. Lightning once again ignited another blaze in the Santiago Canyon area of the Cleveland National Forest. The flames, fanned by winds in excess of 50 mph, charred almost 9000 acres before being brought under control. The steep terrain of the Santa Ana Mountains, coupled with heavy brush, made this fire particularly difficult to extinguish. Dozens were evacuated, but fire fighters were able to save the communities of Foothill Ranch and Portola Hills.