Firefighters contained a grass fire in Vallejo, near the Interstate 80 and 780 connector, by Wednesday evening.
According to Vallejo Fire Battalion Chief Dave Urrutia, the fire started very slowly until winds picked up.
"The fire started torching up the trees. And the wind picked up," Urrutia said. "We had spotting conditions. The smoke with the wind was just pushing it right across the freeway."
Both directions of I-780 have were shut down to due poor visibility from the fire. Smoke was covering all the lanes in of the highway. The California Highway Patrol had to shut down nearby on and off-ramps, and even I-80 was briefly closed.
The blaze strained Vallejo's fire resources.
"Basically, our whole department was stripped for a little while," Urrutia said. He added the agency had to get help from Solano and Napa counties' fire units.
The fire started around 3:45 p.m. and was contained by 6 p.m. The highway was reopened after the smoke cleared.
The cause is under investigation.