District leaders fearing safety hazards from Tropical Storm Hilary moved to close schools across much of Southern California on Monday.

The nation’s second largest school district, Los Angeles Unified, announced Sunday it would close to allow staff time to check buildings for damage from the rare West Coast tropical storm — and to avoid potentially dangerous bus rides to school. San Diego Unified pushed the start of its school year to Tuesday, but asked staff to report to work if they could do so safely.

Several other school districts in Los Angeles County, including in Pasadena, also announced plans to close, bracing for the storm to swirl northeast and risk flooding throughout the region.