1997 GMC Suburban Owner's Manual - Page 214

Hydroplaning usually happens at higher speeds. There just isn't a hard and fast rule about hydroplaning. The best advice is to slow down when it is raining. City Driving Driving Through Deep Standing Water I NOTICE: If you drive too quickly through deep puddles or standing water, water can come through your in engine's air intake and badly damage your engine. Never drive through water that slightly is lower than the underbody your vehicle. If you of can't avoid deep puddles or standing water, drive through them very slowly. Some Other Rainy Weather Tips Besides slowing down, allow some extra following distance. And be especially careful when you pass another vehicle. Allow yourself more clear room ahead, and be prepared to have your view restricted by road spray. 0 One of the biggest problems with city streets is the amount of traffic on them. You'll want to watch out for what the other drivers are doing and pay attention to traffic signals. Have good tires with proper tread depth. (See "Tires" in the Index.) 4-32