Very strong high pressure developed in the upper atmosphere across the desert southwest during the middle of June, beginning on Saturday, June 18th and continuing into the middle of the following week. The very warm temperatures aloft, combined with dry air and sunny skies allowed high temperatures to climb to dangerous levels across the lower deserts each day. Desert high temperatures on Saturday reached or exceeded 110 degrees in many locations and by Sunday, many hotter deserts ranged between 115 and 120 degrees. An Excessive Heat Warning was issued for all of the lower Arizona deserts, starting 1000MST Sunday and continuing through the middle of the following week. The dangerous heat led to the deaths of multiple people, including a mountain biker in the greater Phoenix area during the morning hours on Sunday, June 19th.

Excessive Heat in GREATER PHOENIX AREA, ARIZONA
From 19-JUN-16 10:00:00 to 19-JUN-16 20:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

Unusually strong high pressure aloft developed across Arizona during the middle of June, beginning Saturday June 18th and persisting into next week. The strong high pressure, combined with dry air and sunny skies, led to very dangerous heat across the greater Phoenix area on Sunday June 19th. An Excessive Heat Warning was in effect starting at 1000MST and continuing through the evening hours; the high temperature in Phoenix reached 118 degrees which set a new record for the date. This dangerous heat led to the death of a mountain biker in the Phoenix Mountain Preserve during the morning hours. According to spokesman Captain Larry Subervi of the Phoenix Fire Department, fire crews responded to reports of an adult with heat related issues about 1 mile from the Desert Vista Trailhead shortly before 0900MST. This was in the area near Interstate 17 and Jomax Road. The 28 year old woman, a personal trainer, had set out biking on the trail with two friends at about 0600MST and they all had water. Shortly before 0900MST, her friends - who are doctors - started CPR and called 911. She soon stopped breathing. Crews reached the woman about 0930MST and continued to provide aid while airlifting her to the parking lot where an ambulance awaited. According to Captain Subervi, she was transported to a local emergency room in extremely critical condition and she lost her pulse due to the exhaustion. He indicated that there were no other injuries and her condition was 100 percent heat-related illness. The woman, who was an experience biker, became tired in the heat and told her friends that she could not continue before gaining an altered mental status. Tom Grace, a technician on the helicopter that airlifted her off the trail, said that the operation was one of the riskiest types of rescues performed by the department due to the heat and the location of the woman.

Excessive Heat in CENTRAL DESERTS, ARIZONA
From 18-JUN-16 10:00:00 to 18-JUN-16 20:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Very strong high pressure aloft developed across Arizona during the middle of June 2016, beginning on Saturday June 18th and persisting into early next week. In combination with dry air and sunny skies, the strong high pressure led to the development of dangerous heat across the lower central deserts. The high temperature for the day was 111 at Phoenix and although an Excessive Heat Warning was not yet in effect, heat impact level data suggested that borderline warning conditions had already developed across the greater Phoenix area and northern Pinal county. According to the Pinal County Sheriff's Office, a 25 year old man died while hiking on the Peralta Trail in Gold Canyon during the afternoon hours on June 18th. The victim died as a result of exposure to extreme heat; search and rescue teams were called out to the trail just after 1330MST. According to the Sheriff's Office, a friend told deputies that the victim started hiking at 0730MST for what was to be a day hike; unfortunately he ran out of water after just a few hours. Shortly thereafter he exhibited signs of heat illness and the friend called 911 for help. The man's condition continued to get worse, he lost consciousness and never recovered. This was just one of three heat-related emergency calls within a four hour period on Saturday in the Superstition wilderness. The other two victims ended up with just minor heat-related injuries.