GMC 1995 Jimmy Owner's Manual page 180

Driving too fast through large water puddles or even going through some
car washes can cause problems, too. The water may affect your brakes. Try
to avoid puddles. But if you can't, try to slow down before you hit them.
Hydropraning
Hydroplaning is dangerous. So much water can build up under your tires
that they can actually ride on the water. This can happen if the road is wet
enough and you're going fast enough. When your vehicle is hydroplaning, it
has little or no contact with the road.
Hydroplaning doesn't happen often. But it can if your tires haven't much
tread or if the pressure in one or more is low. It can happen if a lot of water
is standing on the road. If you can see reflections from trees, telephone
poles, or other vehicles, and raindrops "dimple" the water's surface, there
could be hydroplaning.
Hydroplaning usually happens at higher speeds. There just isn't a hard and
fast rule about hydroplaning. The best advice is to slow down when it is
raining.
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