(This story was updated with new information.)
Heavy rain, winds approaching 50 mph and half-inch-sized hail were seen Monday afternoon in parts of the Coachella Valley and the surrounding San Jacinto mountains as strong thunderstorms moved through the area. The storms had passed before sunset Monday evening.
Palm Springs received nearly half an inch of rain, according to the National Oceanic and Atmospheric Administration, while Coachella 0.20 inches.
Rain did not fall evenly across the valley, even in areas that are close together. While the NOAA recorded 0.44 inches of rain at Palm Springs International Airport, one weather station Cathedral City received only 0.04 and another in Cathedral Canyon got 0.29 inches. Desert Hot Springs received no rain, according to the federal agency.
The highest rainfall recorded by the National Weather Service's San Diego office occurred south of Palm Springs, at the Palm Canyon Creek station, which is at 700 feet of elevation and was inundated with 1.42 inches of rain. Mount San Jacinto was also subjected to high totals, receiving 1.03 inches. That station is at 8,616 feet.
Monday's rainfall more than doubled the monthly average in the Palm Springs area. NWS says the region typically gets an average of 0.14 inches in August.
The agency also recorded 3,886 lightning strikes across Riverside County, 178 of which were "cloud-to-ground" strikes.
The NWS issued a flash flood warning at 3 p.m. for most of the western side of the Coachella Valley, as well as Whitewater and Highway 74 between Anza and Palm Desert, warning of "life-threatening flash flooding of creeks and streams, urban areas, highways, streets and underpasses."
Powerful storm begins
The weather service first reported tracking a storm over Mt. San Jacinto at 2 p.m. The storm system then began to move eastward into the Coachella Valley.
“Gusty winds could knock down tree limbs and blow around unsecured objects,” the weather service said as the storm started into the valley. “Minor hail damage to vegetation is possible.”
The weather service advised people to seek shelter inside during the storms. Much of the Coachella Valley was affected, along with Whitewater, Sky Valley and other nearby areas.
The weather service said up to an inch of rain had been recorded in some areas by 2:30 p.m. and warned people to move indoors because of lightning strikes.
"In hilly terrain there are hundreds of low water crossings which are potentially dangerous in heavy rain," the weather service added. "Do not attempt to cross flooded roads."
The weather also brought the temperature down dramatically. As of 3:30 p.m. Monday, the National Weather Service showed the temperature as 71 degrees at Palm Springs International Airport, on a day with predicted highs of just over 100 degrees. After the storm cleared, temperatures rose into the low 80s by the evening.
The stormy weather in Palm Springs could continue for another day, as there’s a 40% chance of precipitation in Palm Springs on Monday night and a 60% chance during the day Tuesday, according to the weather service. The chances drop starting Tuesday night.
The weather is expected to be mostly sunny with highs in the low 100s starting Thursday through the weekend.
Storm causes road closures and delays
Cathedral City announced several street or late closures Monday due to the rainstorm.
Dinah Shore Drive was closed in both directions between Cathedral Canyon and Via De Anza, but later reopened. Two southbound lanes were closed on Date Palm Drive at Los Gatos, leaving only one lane open.
"Our crews are working hard and will remain on site until water recedes and roads can safely reopen," the city shared on social media.
A tree was also reported down at Ocotillo Park, and a crew from Desert Recreation District was responding.
La Quinta paving work on Highway 111 delayed to Tuesday
Due to Monday's inclement weather, work on the Highway 111 Pavement Rehab Improvement Project between Washington Street and Jefferson Street in La Quinta was postponed until Tuesday.
The westbound lanes will remain closed, with paving rescheduled from 6 p.m. on Tuesday, Aug. 26, through 6 a.m. on Wednesday, Aug. 27. The reopening is now set for Thursday, Aug. 28.
All eastbound lanes and driveways along Highway 111 between Washington Street are now open.
Palm Springs Aerial Tramway closed for the remainder of Monday
At 3:30 p.m., the Palm Springs Aerial Tramway suspended operations for the remainder of the day due to heavy rainfall. The Tram Cam, which shows a live feed on the tramway's website, recorded an accumulation of 2.56 inches of rain on Monday.
East valley power outages, flood warning
An unplanned power outage affected the unincorporated community of North Shore, near Mecca and the Salton Sea, beginning around 3:34 p.m. on Monday.
According to IID's website, about 1,109 customers were without power at one point. But as of Monday evening, the outage was no longer listed on IID's website.
IID advises customers experiencing outages to call 760-335-3640 or 1-800-303-7756.
As the storm continued heading east, the National Weather Service issued a flash flood warning at 4:42 p.m. on Monday for the eastern Coachella Valley — including Coachella, Thermal and Mecca — in effect until about 5:41 p.m., warning of "minor flooding in low-lying and poor drainage areas" as well as "water over roadways."
At the time the warning was issued, local law enforcement reported heavy rain from thunderstorms in the area. Minor flooding was already occurring, with .25 to .5 inches of rainfall recorded.
The weather service said an additional .25 inches of rain was expected, which could result in minor flooding.
Flooding prompts warnings at Joshua Tree National Park
Joshua Tree National Park reported that "severe monsoonal storms" hit the park Monday, with flash flooding reported both inside the park and along its boundary — especially near the north entrance and into Twentynine Palms.
"Do not attempt to drive through moving water on roadways," the park advised on its website. "Avoid unnecessary travel."
Between one and two inches of rain had been recorded, with a warning of "life-threatening flash flooding" of creeks and streams, as well as in urban areas, highways, streets and underpasses.
"Flooding is occurring or is imminent. It is important to know where you are relative to streams, rivers, or creeks which can become killers in heavy rains. Campers and hikers should avoid streams or creeks," the National Weather Service's Phoenix office said.
The west entrance of Joshua Tree National Park on Park Boulevard, the park's busiest entry point, was already scheduled to close to all vehicle traffic from Monday, Aug. 25, through 6 p.m. on Friday, Aug. 29. The closure allows the park service to do pavement work as it prepares to open a new entrance station farther into the park with more entry kiosks, as a way of trying to prevent traffic backups.