Parts of the West are under excessive heat warnings and officials say multiple record-high temperatures are expected – with some areas already reaching them. Temperatures will only get hotter on Thursday, which was expected to be the hottest day of the heat wave for most areas and the weekend is expected to be 10 to 15 degrees above normal, according to the The National Weather Service Las Vegas. 

NWS issued warnings of dangerous heat waves in parts of California, Nevada and Arizona on Monday. On Thursday they extended the heat warning for some areas through Saturday.

High temperatures through the weekend will run 10-15 degrees above normal, with Thursday being the hottest day in the stretch. Numerous record high temperatures may be set. pic.twitter.com/XRdNNVxRuR

— NWS Las Vegas (@NWSVegas) June 4, 2024

The NWS HeatRisk map, which monitors the extreme temperatures, takes into account how unusual the heat is for this time of year, how long it will last and if there is an elevated risk of health impacts. The map shows many places are facing "major" or "extreme" heat levels this week, meaning they are well above normal temperatures. 

With well above normal temperatures, little overnight relief, & the duration of the heat- HeatRisk will reach "Major" to "Extreme" levels in many areas. An Excessive Heat Warning is in effect for those areas. To find HeatRisk for your location, find it at https://t.co/aUon3jXa1j pic.twitter.com/WwUDDKwvh2

— NWS Las Vegas (@NWSVegas) June 4, 2024

Las Vegas and Death Valley are in the extreme category, meaning there will be little to no overnight relief and the heat could impact health. In the Southwest, Bracketville, Texas, near the state's Western border with Mexico, is in the extreme category.

Record-breaking temperatures in the West

While heat is common in places like Las Vegas, Thursday's 111 degree Fahrenheit heat there broke a daily record set in 2010 by one degree, according to NWS Las Vegas. And on Friday, the heat is expected to break another daily record.

Early Thursday morning, it was already 100 degrees in Las Vegas – about 4 degrees above the historic daily average, according to Weather Underground.

Places like Bishop, California, Kingman, Arizona, and Death Valley in California have already have or are expected to break daily records this week.

Death Valley National Park is warning people temperatures can be between 100 degrees to 130 degrees and walking is not advised after 10 a.m. 

In Phoenix, Thursday was expected to be the hottest day of this year, with areas near the desert seeing 110 degrees or higher for the first time in 2024, according to NWS Phoenix. On Thursday morning the low temperature of 85 degrees was already 9 degrees above normal for this time of year,

To try and prevent wildfires during the heat wave, the Arizona Department Forestry and Fire Management has issued fire warnings for several counties, advising people not to light camp fires, go target shooting or set off fireworks. 

NWS Los Angeles warned that Wednesday and Thursday would see the hottest temperatures during the heat wave. The deserts were expected to be between 98 degrees to 108 degrees and the mountains and interior valleys between 92 degrees to 102 degrees. They warned drier conditions and breeze will lead to an increased risk for grass fires.

Even California's Bay Area is experiencing higher than normal temperatures thanks to a heat dome over the Western U.S. A heat advisory is in effect from Tuesday through Thursday for the Sonoma coastal range, North Bay interior mountains and valleys, and East Bay hills and valleys, according to CBS News Bay Area. Inland temperatures will been in the 90s up to 100 egrees.

California has entered phase 2 of its Extreme Temperature Response Plan, CBS Los Angeles reports. During this phase, coordination on safety between local and state agencies increases after NWS makes predictions on extreme weather.

NWS predicted Tuesday that Central Valley could reach up to105°F degrees during the heat wave and Death Valley National Park could reach 118 degrees to 121 degrees.

Gov. Gavin Newsom's office blamed changing climate for the more intense and frequent heat waves. Each year, extreme heat kills more Americans than other extreme weather events like wildfires, droughts and floods, Newsom's office said in a statement.

Keeping safe in a heat wave

To try to prevent heat-related illnesses, NWS advises you slow down during a heat wave – try to move strenuous activities to the cooler parts of the day and to cooler areas. Dressing for the weather, staying out of the sun, eating light and hydrating is also advised. 

Spending time in air conditioning is also good and if you have a fan, don't point it directly at your body if the heat is over 90 degrees because the dry air can dehydrate you faster, according to NWS.

Checking on the elderly and sick as well as kids and pets is also recommended.

Heat related illnesses include heat stroke, which can cause confusion or loss of consciousness, and heat exhaustion, which can cause nausea, headache, thirst and heavy sweating, according to the CDC.

If either of these illnesses occur, you should call 911 right away. For heat stroke, you should cool the person down by moving them into the shade or cooler area, remove their clothes and wet their skin.

For heat exhaustion, which is caused by excessive sweating and is likely to effect the elderly, people with high blood pressure or those who work outside, you should move the person to a cooler area, give them liquids and try to cool their skin by removing their clothes and using a cold compress.

In:
• Heat
• Severe Weather
• Excessive Heat Warning

Caitlin O'Kane

Caitlin O'Kane is a New York City journalist who works on the CBS News social media team as a senior manager of content and production. She writes about a variety of topics and produces "The Uplift," CBS News' streaming show that focuses on good news.