RIVERSIDE -

Cal Fire crews today will go into 24-hour stand-by mode at fire stations in Riverside, San Bernardino and San Diego counties in the face of tinderbox conditions exacerbated by meager winter rainfall. 

The seasonal workforce increases in Southern California don't typically begin until May or June. 

So far this year, Cal Fire has responded to more than 800 wildfires.

In an average year, its personnel would typically fight fewer than 275 blazes.