Numerous heat-related warnings and advisories are being issued for a dangerous heat wave blanketing the Pacific Northwest to the northern Rocky Mountains this week. High and low temperatures could tie or break records.

The National Weather Service (NWS) urged people in parts of Washington, Idaho, Oregon, Montana, and Northern California to prepare for dangerous triple-digit temperatures this week, with little reprieve due to record-warm overnight temperatures until Thursday.

Here are our latest Key Messages for the Northwest U.S. Heat Wave: pic.twitter.com/UWgydXtZXG — NWS Weather Prediction Center (@NWSWPC) August 14, 2023

“These temperatures combined with the duration of heat, expected to continue through this week, will increasingly pose a heightened health risk, especially for those without adequate air conditioning,” the NWS short range forecast says. The greatest risk is for residents in western Oregon’s interior valleys and lower elevations, which could see “one of the hottest four day stretches” on record.

Tuesday is forecast to reach highs of 105 in Central California, 106 in Idaho, 107 in Oregon and 108 in Washington, according to the NWS. Those temperatures will linger throughout the region until they drop below triple digits on Friday.

The NWS issued a heat advisory for parts of Idaho for the next two days with high temperatures topping 100 degrees and not falling below 75 at night.

The higher temperatures also bring fear for wildfires. Parts of Montana are also projecting triple digit temperatures, high winds and low humidity, which is why the NWS issued fire weather watch warnings. These factors create conditions prime for wildfires, which could be difficult to contain.

Extreme heat was the leading weather-related killer in the United States last year, killing 148 people, the NWS says, including 33 children who died in hot cars. Heat-related incidents can come on quickly and can affect everyone. Young children, the elderly and individuals with underlying medical conditions are particularly at risk, and should take greater precautions during extreme heat events.

Some steps people can take to stay safe includes limiting or eliminating strenuous activities, wearing lightweight clothes and minimizing exposure to the sun. Be sure to take in easy-to-digest foods like fruit or salads and drink plenty of water. Use air conditioners whenever possible, or use fans to expel the hot air from your house. If it’s over 90 inside a home, blowing the fan on people actually dehydrates them, the NWS says.

The National Oceanic and Atmospheric Administration reported Monday that last month was Earth’s hottest July in 174 years, and that the global sea surface hit a record high for the fourth consecutive month. NOAA’s National Centers for Environmental Information says it is “virtually certain” that 2023 will be one of the top five warmest years on record, and there’s a 50% chance it will be the warmest ever recorded.