2008 GMC Envoy Owner's Manual - Page 262

Driving in Mud, Sand, Snow, or Ice When you drive in mud, snow, or sand, the wheels will not get good traction. You cannot accelerate as quickly, turning is more difficult, and you will need longer braking distances. It is best to use a low gear when you are in mud - the deeper the mud, the lower the gear. In really deep mud, the idea is to keep your vehicle moving so you do not get stuck. When you drive on sand, you will sense a change in wheel traction. But it will depend upon how loosely packed the sand is. On loosely packed sand, such as on beaches or sand dunes, the tires will tend to sink into the sand. This has an effect on steering, accelerating, and braking. Drive at a reduced speed and avoid sharp turns or abrupt maneuvers. Hard packed snow and ice offer the worst tire traction. On these surfaces, it is 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. {CAUTION: 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. 4-24