2003 GMC Envoy Owner's Manual - Page 260

Hard packed snow and ice offer the worst tire traction. On these surfaces, it's very easy to lose control. On wet ice, for example, the traction is so poor that you will have difficulty accelerating. And if you do get moving, poor steering and difficult braking can cause you to slide out of control. If the water isn't too deep, drive slowly through it. At faster speeds, water splashes on your ignition system and your vehicle can stall. Stalling can also occur if you get your tailpipe under water. And, as long as your tailpipe is under water, you'll never be able to start your engine. When you go through water, remember that when your brakes get wet, it may take you longer to stop. Driving on frozen lakes, ponds or rivers can be dangerous. Underwater springs, currents under the ice, or sudden thaws can weaken the ice. Your vehicle could fall through the ice and you and your passengers could drown. Drive your vehicle on safe surfaces only. Driving in Water Heavy rain can mean flash flooding, and flood waters demand extreme caution. Find out how deep the water is before you drive through it. If it's deep enough to cover your wheel hubs, axles or exhaust pipe, don't try it - you probably won't get through. Also, water that deep can damage your axle and other vehicle parts. Driving through rushing water can be dangerous. Deep water can sweep your vehicle downstream and you and your passengers could drown.If it's only shallow water, can it still wash away the ground from under your tires, and you could lose traction and roll the vehicle over. Don't drive through rushing water. See Driving in Rain and on Wet Roads on page 4-30 for more information on driving through water. 4-27