Tropical Storm Mario (2025)

Tropical Storm Mario was a strong tropical storm that brought heavy rainfall to Mexico and the Southwestern United States. The fifteenth named storm of the 2025 Pacific hurricane season, Mario developed from a tropical wave that entered the Pacific on September 8. The tropical wave gradually organized over the next couple days, and would coalesce into a tropical depression on September 10 offshore Guerrero. The storm moved slowly, eventually strengthening into a tropical storm on September 12. Thereafter, it tracked near the coast to Mexico, before a developing low-pressure area caused Mario to degenerate to a remnant low on September 13. Mario regenerated back to a tropical storm the following day as it moved slowly northwestward, reaching its peak intensity on September 15 with wind speeds of 65 mph (100 kmh) and a minimum central pressure of 994 mbar. Mario weakened over the next day and degenerated back into a remnant low before fully dissipating on September 18.

Mario caused flash flooding in several Mexican States. In Michoacán several homes were damaged due to flooding and cars, motorcycles and pets were washed away. In Guerrero heavy flooding was reported. . In Baja California Sur, homes, vehicles and infrastructure were damaged by flooding, and one man was killed by lightning associated with the storm. Mario also contributed to moisture that caused flash flooding in the Southwestern United States, with widespread reports of over a half inch of rain. In addition, a toddler was killed after being swept away in a vehicle. All told, 2 fatalities occurred in relation to Mario, and the storm caused $40.7 million in financial losses.

On September 8, a tropical wave entered the far eastern Pacific from Central America.^[1] The disturbance continued to organize and was designated as Invest 95E the next day.^[2] The disturbance began showing signs of organization on September 10, as it tracked just offshore of the coast of southern Mexico,^[3] and was designated Tropical Depression Thirteen-E the following afternoon. The depression began moving west-northwestward due to the influence of a ridge over northern Mexico and Texas.^[4] The depression continued to organize with convection beginning to develop around its center.^[5] As the depression continued its west-northwestward track on the morning of September 12, it strengthened into Tropical Storm Mario about 25 mi (35 km) off the coast of Guerrero.^[6] When it formed, tropical storm force winds only extended 25 mi (40 km) from its center, prompting the National Hurricane Center to label it "mini".^[7][8] Later that day, a large low-pressure area began developing to the south of Mario causing the convection within the system to decrease and weaken into a tropical depression.^[9] Weakening continued throughout the night, and Mario degenerated into a remnant low early on September 13.^[10]

The remnants of Mario continued to produce disorganized convection as it moved slowly westward through the day.^[11] Convection organized and deepened, and by the next morning, a well-defined circulation had reformed. As a result, Mario redeveloped as a tropical storm just southeast of Socorro Island and began moving west-northwestward on September 14.^[12] However, easterly wind shear displaced convection within the system to the west, preventing any significant strengthening.^[13] However, the cloud tops in the system continued to persist and the system began to develop a better defined curved banding, allowing Mario to strengthen.^[14] During the afternoon of September 15, the storm began to turn northwestward, moving between a mid-level ridge over northern Mexico and a mid-level low to its northwest, and peaked with sustained winds of 65 mph (100 km/h) and a minimum central pressure of 994 mbar.^[15][16] Later that day, however, a weakening trend began as Mario moved into cooler waters.^[17] The storm weakened into a tropical depression on the afternoon of September 16, about 495 mi (800 km) west of the southern point of the Baja California peninsula,^[18] and later degenerated into a remnant low.^[19] The low then dissipated on September 18 at 12:00 UTC.^[16]

Prior to the storm approaching, a tropical storm watch was issued for Michoacan.^[20] However, it was discontinued when Mario was downgraded to a tropical depression.^[21] Forecasters warned that the storm could produce 1-3 inches of rain in some areas.^[22] A flash flood warning was additionally in effect through 14 September.^[23] A green alert was issued for Jalisco.^[24] A blue alert was issued for Guerrero and Oaxaca.^[25] The ports of Lazaro Cardenas and Cabo San Lucas were closed.^[26][27] Classes in Michoacan were suspended prior to the arrival of the storm.^[28]

In Chiapas, an interaction of multiple weather systems, including moisture from the trough of low pressure that spawned Mario, caused heavy rain in the state. More than 140 mm (5.5 in) of rain fell in some areas. More than fifteen homes and 27 neighborhoods were flooded.^[29][30] In Guerrero, flooding, fallen trees, and power outages were reported.^[31] A total of 9.06 in (230 mm) of rain fell in Coyuca de Benítez.^[16] Landslides caused damage along roadways, isolating several communities.^[32] Rip currents were reported along beaches in Colima.^[33]

A trough caused remnant moisture from Mario to be advected northward into Baja California Sur.^[16] Several homes, vehicles, and roads were damaged by floodwaters.^[34] At least 64 homes and six neighborhoods were inundated.^[35][36] Damage from the storm forced the closure of ten schools.^[37] A portion of a highway in In San Ignacio collapsed, cutting off several local communities and causing a gas truck to fall in.^[38][39] Strong winds caused three utility poles to fall.^[40] Over 250 families were left homeless following the storm.^[41] Flooding caused the cancellation of an Independence Day celebration in Mulegé.^[42] In Cabo San Lucas and San José del Cabo, sinkholes and flooding on roadways caused widespread traffic disruption. Drainpipes were damaged, causing wastewater to flood several neighborhoods and shopping centers.^[43][44] Several people were rescued after two vehicles and a semi-trailer became stranded while attempting to cross a flooded stream.^[45] In Ciudad Constitución, winds gusted up to 45 mph (70 km/h).^[16] A 37-year-old man was struck and killed by lightning during the passage of the storm.^[46]

Before the storm, parts of the Southwestern United States were placed under a slight risk of excessive rainfall.^[47] The remnants of Mario prompted flood and flash flood warnings throughout Central and Southern California.^[48][49] Officials warned that lightning could spark potential fires.^[50] Thunderstorms were also reported, with over nine thousand lightning strikes recorded. Heavy rainfall was also recorded in the state, with precipitation peaking at 4.14 in (105 mm) at Running Springs.^[48][49] Near Forest Falls, 1.77 in (45 mm) of rain fell in a single hour.^[51] At San Diego, the rainfall total was 0.45 in (11 mm), well above the monthly average and pushing September to its seventh highest rainfall total.^[52] In Imperial County, winds gusted up to 64 miles per hour (103 km/h). On California State Route 111, a semi-truck flipped over.^[53] In Barstow, floodwaters swept away a vehicle, killing a toddler and injuring his father.^[54][55] Two others were injured in a seven vehicle pileup on Interstate 10.^[56] Across California, heavy rain triggered numerous landslides, leaving several vehicles stranded.^[57] This was particularly severe in areas such as Oak Glen, which was still recovering from the El Dorado Fire.^[58] Ten people required rescue after becoming stranded on California State Route 38 in the San Bernardino Mountains.^[52] Mudslides and flooding damaged fourteen homes, four outbuildings, one commercial building and destroyed three homes.^[59] At Death Valley National Park, several roads were closed and there was severe flooding in the park, with a quarter of the park's annual precipitation falling during the storm.^[60][61] Over 7,000 customers lost power in Imperial County alone.^[62] However, the rains were noted to have slightly reduced the fire risk in the region.^[63] Further north in the Central Valley, 0.81 in (21 mm) of rain poured down in Fresno.^[64] Damage in California totaled to US$168,000.^[55]

Rainfall at Harry Reid International Airport in Las Vegas reached 0.24 inches (6.1 mm), the wettest day at the airport since May 6.^[65][66] Locally heavy rainfall was recorded in the northern part of the state, but was not universal across the area.^[67] In Clark County, strong winds downed a tree, killing a horse. Damage totaled to US$5,000.^[68] Rainfall was also recorded in Arizona, peaking at 0.3 in (7.6 mm) in Tempe.^[69] Street flooding forced several road closures.^[70] Five children and a dog were rescued from rising floodwaters.^[71] Slippery roads caused an SUV to veer off a road.^[72] In Phoenix, three people were injured after slippery roads caused a traffic collision. One person was rescued after their car was swept away by floodwaters.^[73] At least 1,800 households lost power during the storm.^[74]

A local emergency was declared in Imperial County in the aftermath of the storm.^[75] A shelter was also opened in Calexico.^[62] Congressmen Raul Ruiz visited the Imperial Valley to look at the damage the storm caused in the aftermath.^[76] In addition, Caltrans launched a $9.7 million project to restore California State Route 38 through the San Bernardino National Forest.^[77] Officials estimated total road damage and the cost to repair the damage at US$40.7 million.^[78]

In El Salvador, the tropical wave that spawned Mario caused urban flooding. A woman was injured after being swept away by an overflowing drainpipe. More than 10 families were evacuated from flooded areas.^[79]

• Weather of 2025
• Tropical cyclones in 2025
• Other tropical cyclones of the same name
• List of Baja California Peninsula hurricanes
• List of California hurricanes
• Tropical Storm Ileana (2018) – took a similar track

• The National Hurricane Center's advisory archive on Tropical Storm Mario