Warmer temperatures may bring more instances of hypothermia, according to the National Weather Service.
High pressure is expected to build over Western Nevada causing temperatures to increase into the 90s by Sunday, 20 degrees warmer than average for mid-May, according to a special statement issued today.
Forecasters predict temperatures above 8,000 feet will rise above 50 degrees causing the snowpack to melt rapidly and increase stream flows over the weekend.
While people are enjoying Sierra lakes, rivers and streams, the weather service warns that they'll be extremely cold, swift and dangerous this weekend.
"Although it may be tempting to jump into rivers and lakes, water temperatures are cold and may lead to hypothermia," an official said. "Current water temperature estimates are in the mid 40s and 50s.
It takes only minutes for the effects of hypothermia to be felt. Rapidly lowering body temperature can be fatal.
Warning signs include uncontrolled shivering, disorientation, slurred speech, drowsiness and exhaustion.
The weather service is warning parents to keep a close eye on their children, since they can be affected more quickly than adults and can easily be swept off their feet by swift currents.
