The Interstate 10 bridge, which collapsed in eastern California on Sunday in a flash flood caused by an unusual sudden downpour, passed state inspections in March and showed no structural issues, officials said Monday.

The bridge in the California desert between Los Angeles and Phoenix, Arizona collapsed after water rushing through a normally dry gully eroded the land around it. All traffic was stopped in both directions at the bridge, around 50 miles from the Arizona border, which sees around 27,000 vehicles in either direction on an average day.

Nearly seven inches of rain fell in the nearby town of Desert Center on Sunday, setting records for rainfall in drought-stricken California in what is typically a very dry month. The collapse occurred as rains were falling at a rate of 1.5 inches per hour.

Stuck in Palm Springs on the way back to Phoenix after a bridge collapses over the interstate… Whole thing is shut down. What luck — Connor (@SailorJurgy) July 20, 2015

The bridge should have been fine had the flood come straight down the gully, but it came at an angle that pushed the water to one side, the state’s Department of Transportation spokeswoman Vanessa Wiseman told journalists Monday. It is not clear what prompted the flood waters to change direction.

Photo: Investigators on scene of bridge collapse on Interstate-10 in Desert Center, Calif. — @KESQ: pic.twitter.com/Rb00Vxcn03 — Eugenio Bertolaccini (@EBertolaccini) July 20, 2015

Inspection in March showed no structural issues, though the eastbound span of the bridge was deemed “functionally obsolete.” Wiseman said that reflected not the bridge’s strength or durability, but the fact that it was built in the 1960s and requires motorists to slow on approach.

Looks like to avoid the 10 FWY heading to Arizona due to the bridge destroyed interstate 40 FWY is another alternative — Hector Morales (@DashingHector) July 21, 2015

No timeframe has been given for when either direction of the interstate would reopen.