Update: Excessive Heat Warnings This Week
The Heat Advisory issued for Yosemite National Park (outside of the Valley floor) has been extended until 10 AM Thursday. The National Weather Service has issued an Excessive Heat Warning for the northern San Joaquin Valley, from 11 AM this morning (Wednesday) until 8 PM Friday. The Heat Advisory that is already in effect for the western slope of the northern Sierra Nevada and the Excessive Heat Warning for the Mother Lode, will also expire at 8 PM Friday. Finally, the Excessive Heat Warning currently in effect for Mariposa County, the Yosemite National Park Valley floor, and the central San Joaquin Valley, will end at 10 AM Saturday.
High temperatures are 15 to 20 degrees above normal. This is creating dangerously hot conditions, with high temperatures ranging from 90 to 115 degrees, depending on your exact location. Widespread areas of Major to Extreme HeatRisk continue to exist.
Such well-above-normal temperatures continues to have a significant impact and is making outdoor activities more likely to cause heat-related illnesses than what most folks are used to, even in the upper Sierra Nevada.
This level of rare, long-duration extreme heat with little to no overnight relief affects everyone, especially those without effective cooling and/or adequate hydration. Heat related illnesses increase significantly during extreme heat events, particularly for those working or participating in outdoor activities.
Take extra precautions when outside. Wear lightweight and loose fitting clothing. Try to limit strenuous activities to early morning or evening. Take action when you see symptoms of heat exhaustion and heat stroke.
To reduce risk during outdoor work, the Occupational Safety and Health Administration recommends scheduling frequent rest breaks in shaded or air conditioned environments. Anyone overcome by heat should be moved to a cool and shaded location. Heat stroke is an emergency! Call 9 1 1.
There will be impacts likely in most health systems, heat-sensitive industries and infrastructure.
Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors.
Do not leave young children and pets in unattended vehicles. Car interiors will reach lethal temperatures in a matter of minutes.
There is limited overnight relief with low temperatures ranging from the upper 60’s to the lower 80s.
Area waterways will continue to run cold and fast, creating dangerous conditions for those seeking relief in rivers and lakes.
Stay cool, stay hydrated, stay informed.
