Downed tree blocking WB lanes of I-8

SAN DIEGO — A downed tree blocking three of the four westbound lanes of Interstate 8 just west of 70th Street in the La Mesa area was reported around 11 a.m., according to the California Highway Patrol.

A short time later, a crash involving an overturned semi-truck and van in Alpine closed all WB lanes on I-8 at Japatul Road. It’s not immediately known whether high winds caused the crash.

A red flag wildfire warning from the National Weather Service remained in effect Thursday and was set to expire late Saturday night, while a high wind warning was set to expire at 4 p.m. Friday. The red flag warning signifies a high risk of wildfire because of high winds and low humidity — forecasters said minimum humidity levels were at 5 percent Thursday — while the high wind warning indicates sustained wind speeds of 40 miles per hour and 58-mph gusts.

Even stronger gusts were expected throughout Thursday potentially exceeding 80 mph, according to the U.S. Forest Service. Cal Fire officials said the Southern California region is bracing for “epic winds … and extremely dry conditions.”

“The fire potential with this Santa Ana event is extreme,” the Forest Service said on its Santa Ana Wildfire Threat Index page. “Easterly winds of 20 to 45 mph can be expected with gusts exceeding 80 mph over the higher terrain and in the more wind prone areas. Humidity will be in the 5- to 15- percent range. Fires will spread very rapidly through all fuel types. Any new fires will have a high probability of becoming large in a short period of time.”

The conditions expected throughout San Diego County were even more extreme than the dry, windy conditions that fanned the three wildfires that have burned more than 20,000 acres in the Los Angeles area, as well as the 90,000-acre Thomas Fire in Ventura County.