Arizona, 2021

Heat in Arizona, July 21, 2021

July 21, 2021 · NWS TWC · 1 event in 1 county or zone

Hot temperatures of 100 to 105 degrees on the Tohono O'odham Nation were experienced on July 21. The Pima County Medical Examiner confirmed that heat was the primary cause of death for one male found in the desert near Ali Chugk and a contributing factor of another male found near Vamori.

Where it happened

Every event with a place to put it; 1 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.

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  • Floods
  • Wind
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  • Winter weather
  • Heat and drought
  • Cold
  • Fire, smoke and dust
  • Marine and coastal
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The toll

Deaths
2
Injuries
0
Property damage
None recorded
Crop damage
None recorded
Events
1

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

What happened

The episode as NWS TWC wrote it up.

Hot temperatures of 100 to 105 degrees on the Tohono O'odham Nation were experienced on July 21. The Pima County Medical Examiner confirmed that heat was the primary cause of death for one male found in the desert near Ali Chugk and a contributing factor of another male found near Vamori.

What forecasters said that day

The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Tucson, AZ wrote its last area forecast discussion before the first event at Jul 21, 2:59 AM MST, 7 hours 1 minute earlier.

Area forecast discussion, Jul 21, 2:59 AM MST, 7 hours 1 minute before
Area Forecast Discussion
National Weather Service Tucson AZ
259 AM MST Wed Jul 21 2021

.SYNOPSIS...An approaching weather system from the east will bring
widespread showers and thunderstorms to the area, especially from
Thursday evening through late Saturday. Locally heavy rainfall
combined with a saturated ground from recent rains may result in
flash flooding and flooding by Saturday night. Thereafter, a
decrease in daily shower and thunderstorm activity can be
anticipated Sunday afternoon into early next week. Otherwise, high
temperatures will be near normal with the exception of Friday into
the weekend when below average readings can be expected.

&&

.DISCUSSION...An interesting weather pattern will evolve Thursday
into the weekend as an upper low approaches from the east and
becomes quasi-stationary over east-central AZ/west-central NM late
Friday through late Saturday. This scenario resembles an historic
flooding and debris flow event in SE AZ which played out nearly 15
years ago during the last few days of July into August 1st of the
2006 monsoon season. That said, have posted a flash flood watch for
Thursday evening through Saturday evening for all of SE AZ.
Ensembles favored this feature tracking farther west and lifting
northward on Sunday with subsidence in the wake of it over SE AZ.
Thus, expect improving weather Sunday with limited shower and
thunderstorm coverage early next week. High temperatures will remain
near normal except on Friday through Sunday when below normal
readings will occur due to the anticipated rain and cloudiness.

&&

.AVIATION...Valid through 22/12Z.
SCT-BKN clouds at 8k-12k ft MSL much of the period. Widespread
SHRA/TSRA developing this afternoon and evening. Expect brief MVFR
CIGS/VSBYS and mountain obscurations around TSRA along with gusty
outflow winds, potentially in excess of 45 kts with the strongest
storms. Otherwise, SFC wind generally less than 12 kts following
diurnal trends. Aviation discussion not updated for TAF amendments.

&&

.FIRE WEATHER...Monsoon continues to be active into this weekend
with scattered to widespread showers and thunderstorms. In
particular, Thursday through Saturday look extremely active with
heavy rainfall and flooding issues anticipated. While in this
pattern, showers and storms will be possible at all hours of the day
and overnight. Storms will also be capable of producing very gusty
winds in excess of 35 mph and numerous lightning strikes. Daytime
temperatures will remain below normal. 20-foot winds will generally
be less than 15 mph when not influenced by thunderstorms. Daytime RH
mainly above 25 percent into next Monday, with very good overnight
recoveries.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
   Flash Flood Watch from Thursday evening through Saturday evening
   for AZZ501>515.
&&

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The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

1 heat. Local standard time, as filed.

Heat, Tohono O Odham Nation

When
July 21, 10:00 AM MST to 8:00 PM MST
Where
Tohono O Odham Nation forecast zone
Deaths
1 direct, 1 indirect
Reported by
County Official
Coordinates
32.501, -111.567 (the zone’s center; the record gives no point)

Temperatures 5 to 9 degrees above normal of 100 to 105 degrees, occurred on the Tohono O'odham Nation causing the Moderate Heat Risk category to be reached on July 21. The Pima County Medical Examiner confirmed that heat was the primary cause of death for one male found in the desert near Ali Chugk and a contributing factor to one male found near Vamori.

The people who died

As the offices recorded each death: direct deaths were caused by the weather itself, indirect ones by something it set in motion.

EventDateAgeSexWhereKind
Heat, Tohono O Odham Nation2021-07-2127MaleOutside/Open AreasDirect
Heat, Tohono O Odham Nation2021-07-2128MaleOutside/Open AreasIndirect

What these are

Heat
Heat below excessive heat criteria that still caused deaths, injuries or significant impacts.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

More

Every storm in Arizona in 2021Every state in 2021This day in weather historyWarnings in Arizona, July 2021

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 976595.