UPDATE: Caltrans has now opened the fast lane.
Northbound lanes of Highway 101 just north of West Tefft Street in Nipomo are closed due to an overturned truck that spilled a load of irrigation pipes.
The CHP has issued a Sig Alert about the closure. Motorists should detour at Tefft and use Pomeroy or Thompson roads as alternate routes.
Right now there is no estimated time of reopening the freeway lanes, said Caltrans.