GMC Yukon Denalid Owner's Manual page 372

Stalling on an Incline
If your vehicle stalls when you are crossing an
incline, be sure you, and any passengers, get out
on the uphill side, even if the door there is
harder to open. If you get out on the downhill side
and the vehicle starts to roll over, you will be
right in its path.
If you have to walk down the slope, stay out of the
path the vehicle will take if it does roll over.
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CAUTION:
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Getting out on the downhill (low) side of a
vehicle stopped across an incline is
dangerous. If the vehicle rolls over, you
could be crushed or killed. Always get out
on the uphill (high) side of the vehicle and
stay well clear of the rollover path.
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.