UPDATE: All lanes are now open.

(KRON) — A sig alert has been issued and southbound lanes three and four on the I-280 are blocked due to a grass fire burning near Los Altos Hills, according to an incident report.

The brush fire is north of Magdalena Avenue on southbound I-280 in Los Altos. The right lanes are blocked.

Drivers should expect delays and use alternate routes to avoid the area. There is no estimated time to reopen the roadway.

This is a developing story. Check back for updates.