GMC 2003 GMT560 T-Series Owner's Manual page 146

Remember, unless you have anti-lock, if you brake so
hard that your wheels stop rolling, you'll just
slide. Brake so your wheels always keep rolling and
you can still steer.
•
Whatever your braking system, allow greater
following distance on any slippery road.
•
Watch for slippery spots. The road might be fine
until you hit a spot that's covered with ice. On
an otherwise clear road, ice patches may
appear in shaded areas where the sun can't reach:
around clumps of trees, behind buildings or
under bridges. Sometimes the surface of a curve
or an overpass may remain icy when the
surrounding roads are clear, If you see a patch of
ice ahead of you, brake before you are on it.
Try not to brake while you're actually on the ice,
and avoid sudden steering maneuvers.
4-28
If You're Caught in a Blizzard
If you are stopped by heavy snow, you could be in a
serious situation. You should probably stay with
your vehicle unless you know for sure that you are near
help and you can hike through the snow. Here are
some things to do to summon help and keep yourself
and your passengers safe:
•
Turn on your hazard flashers.
•
Tie a red cloth to your mirror arm to alert police that
you've been stopped by the snow.