Extreme heat
Temperatures that hover 10 degrees or more above the average high temperature for the region and last for several weeks are defined as extreme heat. During these events, affected areas may experience little, to no, overnight cooling and providing limited relief. Extreme heat events may also occur during weather events that cause a rapid increase of temperature several degrees above normal. While the numerical temperature reading may not seem high, the rapid rise in temperature can cause similar watches and warnings due to the lack of acclimation to the temperature. Excessive heat events have significant health impacts, as well as impact critical infrastructure such as electrical and HVAC systems.
The UW utilizes the National Weather Service for information and accurate temperatures impacting the Seattle area, to include the University of Washington campus. NWS issues multiple products related to heat, including forecasts, watches, advisories, and warnings by location. However, heat affects everyone – even people in the same location – differently. The NWS has developed the HeatRisk prototype to better address heat risk to individuals and communities. The NWS HeatRisk forecast provides a quick view of the risk posed by extreme heat over the upcoming seven days. HeatRisk is portrayed in a numeric and color scale and provides one value each day that indicates the approximate level of heat risk concern for any location, along with identifying the groups who are most at risk
Before
Prevention
Ensure everyone responsible for outdoor work or outdoor programs takes the UW EH&S Outdoor Heat Exposure and Heat-Related Illness online training
- Drink more fluids (nonalcoholic), regardless of your activity level. Don’t wait until you’re thirsty to drink. Warning: If your doctor generally limits the amount of fluid you drink or has you on water pills, ask him how much you should drink while the weather is hot.
- Don’t drink liquids that contain caffeine, alcohol, or large amounts of sugar-these actually cause you to lose more body fluid. Also, avoid very cold drinks, because they can cause stomach cramps.
- Stay indoors and, if at all possible, stay in an air-conditioned place. Electric fans may provide comfort, but when the temperature is in the high 90s, fans will not prevent heat-related illness. Taking a cool shower or bath, or moving to an air-conditioned place is a much better way to cool off.
- Wear lightweight, light-colored, loose-fitting clothing.
- NEVER leave anyone or pets in a closed, parked vehicle.
- Although any one at any time can suffer from heat-related illness, some people are at greater risk than others. Check regularly on:
- Infants and young children
- People aged 65 or older
- People who have a mental illness
- Those who are physically ill, especially with heart disease or high blood pressure
Know your Watches & Warnings
- Excessive Heat Warning—Take Action! An Excessive Heat Warning is issued within 12 hours of the onset of extremely dangerous heat conditions. The general rule of thumb for this Warning is when the maximum heat index temperature is expected to be 105° or higher for at least 2 days and night time air temperatures will not drop below 75°; however, these criteria vary across the country, especially for areas not used to extreme heat conditions. If you don’t take precautions immediately when conditions are extreme, you may become seriously ill or even die.
- Excessive Heat Watches—Be Prepared! Heat watches are issued when conditions are favorable for an excessive heat event in the next 24 to 72 hours. A Watch is used when the risk of a heat wave has increased but its occurrence and timing is still uncertain.
- Heat Advisory—Take Action! A Heat Advisory is issued within 12 hours of the onset of extremely dangerous heat conditions. The general rule of thumb for this Advisory is when the maximum heat index temperature is expected to be 100° or higher for at least 2 days, and night time air temperatures will not drop below 75°; however, these criteria vary across the country, especially for areas that are not used to dangerous heat conditions. Take precautions to avoid heat illness. If you don’t take precautions, you may become seriously ill or even die.
- Excessive Heat Outlooks—Be Aware! The outlooks are issued when the potential exists for an excessive heat event in the next 3-7 days. An Outlook provides information to those who need considerable lead-time to prepare for the event.
During
- Move outdoor events and outdoor work to the coolest potions of the day
- Departments and programs conducting outside work or events should self monitor temperatures for their locations and adjust activities accordingly
- Encouraging staff and students to avoid unnecessary outdoor activity
- Encourage remote work or implement your department business continuity plan
- Limit strenuous outdoor activity
- If possible, ensure outdoor work is conducted in teams to ensure more frequent work, rest, hydration cycle and to be on the lookout for heat related injuries
Heat Related Injuries
HEAT STROKE
- Signs:
- Extremely high body temperature (above 103 degrees F) taken orally
- Red, hot and dry skin with no sweat
- Rapid, strong pulse
- Dizziness, confusion or unconsciousness
If you suspect heat stroke, call 9-1-1 or get the person to a hospital immediately. Cool down with whatever methods are available until medical help arrives. Do not give the person anything to drink.
HEAT CRAMPS
- Signs: Muscle pains or spasms in the stomach, arms or legs
HEAT EXHAUSTION
- Signs: Heavy sweating, paleness, muscle cramps, tiredness, weakness, fast or weak pulse, dizziness, headache, fainting, nausea, vomiting
Additional information
- UW Workplace Heat Stress Requirements for Employees and Supervisors
- UW EH&S Outdoor Heat Exposure
- Centers for Disease Control and Prevention
- Federal Emergency Management Agency
- National Weather Service
- UW Business, Academic, and Research Continuity Planning
Keeping updated
- UW Information Line (recorded message) 206-UWS-INFO, Toll Free: 1-866-897-INFO
- Sign up for UW Alert
- Banner alerts on UW Home page
- Your supervisor, department/college administrator or building coordinator