PHOENIX (CN) — Coming off the heels of a cool, wet winter for most of the Southwest, the desert heat is back in full force. Multiple cities across Arizona are under excessive heat warnings, as temperatures in some parts of the state are expected to hover around 115 degrees Fahrenheit for the next few days.

The National Weather Service issued an excessive heat warning on Saturday for the city of Phoenix, initially in effect through the Fourth of July. Today, the service extended the warning to 8 p.m. Friday.

In response, the city of Phoenix closed hiking trails on Camelback Mountain and Piestewa Peak between 11 a.m. and 5 p.m. as long as the heat warning remains in effect. While hiking other Phoenix trails isn’t prohibited during those hours, the city “strongly discourages” doing so. Pets are also banned from all Phoenix trails as long as temperatures remain above 100 degrees.

“We have extended trail and park hours at some popular parks to encourage early morning/late evening hiking, and we have plenty of indoor recreation centers, splash pads and pools for people to use to stay cool,” said Adam Waltz, Phoenix parks and recreation public information officer.

Last year saw 18 days in which hiking restrictions were placed on the two Phoenix mountains.

The National Weather Service issued the same excessive heat warning for most cities in the Phoenix metro, as well as some southern cities like Tucson and Yuma. Nogales, a town split across the U.S.-Mexico border, is under warning until July 5.

Heat is the deadliest weather element in Arizona, according to the National Weather Service. Between 2010 and 2020, the Grand Canyon State saw more than 3,000 heat-related deaths. Maricopa County recorded 425 heat-related deaths in 2022. And heat, matched with the state’s aridity, creates intense fire conditions.

Up in the San Francisco mountains, the Route 66 city of Flagstaff entered stage one fire restrictions on Thursday, prohibiting the use of campfires and coal, charcoal or wood grills anywhere other than developed campsites and picnic areas. Smoking in undeveloped outdoor spaces, lighting fireworks and using open-flame torches are all prohibited as well under stage one restrictions. Stronger restrictions are imposed under stage two, like a full campfire ban.

Coconino National Forest Ranger Matt McGrath said the Flagstaff district typically enters stage one restrictions around May 5, but the unusually wet winter maintained soil moisture into the summer. After floating around the 70s in late June, the city will see highs of nearly 90 degrees this week.

Mountainside cities like Flagstaff don’t only have fire to worry about. Fires that blaze through the forest in the summertime leave the charred land particularly susceptible to intense flooding and debris flows, as the soil can no longer absorb water, and nothing is left to keep the soil itself from sliding down the mountain with the rain. These post-fire floods can wreak havoc on houses and other structures.

Flooding the second leading weather-related cause of death behind heat. Thirty-five Arizonans died due to floods between 2010 and 2020. Nineteen deaths were caused by wildfires.

As of Monday, there are at least 19 wildfires burning in Arizona. Three are burning in the Phoenix metro, one is in northeast Scottsdale and two just west of Buckeye.

Arizona isn’t the only state trying to beat the heat. Parts of Southern California like Santa Clarita, just north of Los Angeles, as well as most of Death Valley, are also under excessive heat warnings through the end of the day, as is the Las Vegas metro area.

To prevent heat-related illness, the National Weather Service recommends avoiding being outdoors as much as possible. If necessary, drink one or two liters of water for every hour spent outside. If outdoor strenuous activity is necessary, limit it to the coolest part of the day, which in Arizona is typically 4 to 7 a.m. If a person becomes confused, dizzy or unconscious in the heat, call 911 immediately.

For those who may not have reliable shelter during an excessive heat warning, the Maricopa Association of Governments manages a heat relief network that gives people options to cool off and hydrate. It also provides heat relief outreach both in cities and at trailheads to distribute water and other supplies and share information on cooling resources.