An intense early-season heatwave pushed temperatures to extreme levels across the southwestern United States between March 18 and 22, 2026, as a persistent high-pressure ridge produced widespread daily and monthly March temperature records. Record heat was reported across Arizona, California, Nevada, and other parts of the western United States.
At least five people were confirmed dead in Oman’s South Al Batinah Governorate by March 23, 2026, after flash floods swept vehicles away in Al-Maawil and Barka during heavy rainfall linked to a low-pressure system.
A 71-year-old woman was reported missing after being swept into the Iao Stream on Maui, Hawaii, at about 11:40 LT on March 21, 2026, while heavy rainfall kept the stream in rapid flow. Witnesses said she became fully submerged and was not seen again. Search operations continued on March 22 using ground, air, and ocean assets.
A strong and shallow earthquake registered by the USGS as M6.2 hit the Samoa Islands region at 15:27 UTC on March 22, 2026. The earthquake occurred at a depth of 10 km (6.2 miles). EMSC is reporting the same magnitude and depth.
A strong and shallow earthquake registered by the USGS as M6.2 hit Tonga at 06:15 UTC on March 22, 2026. The agency is reporting a depth of 10 km (6.2 miles). EMSC is reporting the same magnitude and depth.
A strong and shallow earthquake registered by the USGS and EMSC as M6.7 struck the northern Mid-Atlantic Ridge at 12:16 UTC on March 21, 2026, at a depth of 10 km (6.2 miles).
Storm damage in Hawaii could exceed USD 1 billion as severe flooding from a Kona low affects Oʻahu on March 20–21, 2026, forcing about 5 500 residents to evacuate and triggering emergency warnings over the imminent risk of failure at Wahiawā Dam.
Wahiawa Dam on Oʻahu, Hawaii, was placed under an imminent failure risk alert on March 20, 2026, prompting emergency evacuations in downstream communities, including Haleiwa and Waialua.
Life-threatening flash flooding struck Oʻahu’s North Shore, Hawaii, on March 20, 2026, after a slow-moving Kona low produced more than 330 mm (13 inches) of rain in parts of northern Oʻahu in about 12 hours from the evening of March 19 into the morning of March 20. Flooding in the Haleiwa and Waialua areas cut off road access, prompted evacuation orders, and triggered emergency response operations.
A historic March heat event affected the U.S. Southwest on March 19 and 20, 2026, setting a new March temperature record in Las Vegas, Nevada, and a new highest March temperature ever recorded in the United States near Martinez Lake, Arizona. Multiple daily and monthly records were also broken across parts of Nevada, California, and Arizona, while authorities in Phoenix closed some hiking trails because of heat risk.
