"The L.A. Basin is a big cul-de-sac. To the north and the east we're bounded by some pretty high mountains," said Bill Patzert, a climatologist with the Jet Propulsion Laboratory in La Cañada Flintridge. "The basin is just filling up with this smoke."
He said the smoke would probably remain until Sunday, along with a high-pressure system that has brought sizzling temperatures and red-flag fire conditions.
"We're sitting in the smoke until Sunday. It's going to get hotter and smokier," Patzert said.