Pontiac 2003 Montana Owner's Manual page 294

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.