Several of my fellow bike commuters are talking about the "heavy" rain that's been in the Bay Area. I heard one guy talk about the "sheets" of rain falling from the sky the other week.
For those outside of California, I'll describe the typical California rain storm. Take a spray bottle -- the kind you use to mist your plants. Hold it about six inches from your face and spray yourself until the bottle is empty. That's a heavy rainstorm in the San Francisco Bay Area. I'm not joking. It's not even a drizzle like you guys up in Seattle get. Occasionally we'll even have a mild zephyr to accompany the storm.
A heavy rainstorm in just about any other location is hauling a 30 gallon trashcan up to a second floor balcony and filling with water. Optionally add an 8 pound bag of ice (for the hail), small twigs, frogs, puppies, scrap lumber, etc. Stand under the balcony as several of your friends lift the can up and over so the contents of the trashcan fall directly on you and your bike, with the trashcan tumbling immediately afterwards into you. That's a spring storm anywhere in the U.S. Midwest and South. Of course it's not really a storm unless 80 mph winds knock down utility poles.
This is kind of a sidebar for my article about bicycle fenders at Commute By Bike.