The Weekly Volcanic Activity Report: May 21-27, 2026
New activity/unrest was reported for 4 volcanoes from May 21-27, 2026. During the same period, ongoing activity was reported for 18 volcanoes.
Portugal breaks national May temperature record with 40.3°C (104.5°F) in Mora
Portugal set a new national May temperature record on May 27, 2026, after Mora reached 40.3°C (104.5°F) during an early-season heatwave, according to the Portuguese Institute for Sea and Atmosphere (IPMA). The reading surpassed the previous May extreme of 40°C (104°F), recorded at Pinhão on May 30, 1953, and matched at Termas de Monfortinho on May 30 and 31, 2001.
Flooding claims first weather-related fatality in Cocke County since Hurricane Helene, Tennessee
A 64-year-old woman died after being swept away by floodwaters near her home in Cocke County, Tennessee, on May 28, as 76 to 127 mm (3 to 5 inches) of rain triggered flooding and multiple rescue operations across the county.
Sonic boom rattles South Carolina Midlands, USGS logs M0.0 event near Saint Andrews
Residents across the South Carolina Midlands reported a loud boom and brief shaking late Thursday afternoon, May 28, 2026. The U.S. Geological Survey (USGS) later logged the event as an ‘M0.0 sonic boom’ near Saint Andrews, South Carolina.
Paris enters unprecedented May heat streak as France experiences record-breaking temperatures
France recorded its hottest May day since records began on May 26, 2026, while temperatures climbed to 37.8 °C in southwestern parts of the country on May 28. Multiple stations across France set new all-time May temperature records this week as a prolonged heat dome pushed daytime temperatures into the upper 30s°C (upper 90s°F) and kept nighttime temperatures unusually high across much of the country.
Submarine eruption near Titan Ridge opens new island possibility in the Bismarck Sea, Papua New Guinea
A submarine eruption that began on May 8, 2026, continues in the central Bismarck Sea, about 130 km (81 miles) southeast of Manus Island, Papua New Guinea. The eruption revealed a previously unmapped underwater volcano, now provisionally named Titan Ridge Volcano, in a remote and tectonically active area of the Pacific Ocean.
Open-water deaths rise to 11 during record May heat in the UK
Eleven people have died after getting into difficulty in open water across the UK during a record late-May heat episode. The fatalities include nine children and two adults. The Met Office said 35.1°C (95.2°F) at Kew Gardens on May 26 provisionally broke the UK May and spring temperature record for the second consecutive day.
Early El Niño signals seen in June forecasts for the United States and Canada
NOAA and long-range atmospheric forecast models are increasingly showing early El Niño-related circulation signals over North America as forecasters continue monitoring a developing transition away from ENSO-neutral conditions during summer 2026.
Tropical Storm Jangmi forecast to intensify into a typhoon over the Philippine Sea
Tropical Storm Jangmi was located 1 245 km (774 miles) east of southeastern Luzon at 17:00 LT (09:00 UTC) on May 28, 2026 with PAGASA and JTWC forecasting continued intensification over the Philippine Sea during the next several days.
Heavy rainfall and flash flooding forecast across Texas, the Gulf Coast, and the Appalachians
A Slight Risk area for excessive rainfall remains in effect across southeast Texas, the central Gulf Coast, and parts of the Ohio Valley into the central Appalachians where slow-moving thunderstorms may produce flash flooding over saturated ground through May 27. Deep Gulf moisture and a slow-moving weather pattern are forecast to fuel multiple rounds of heavy rain from southeast Texas to the central Appalachians, increasing the risk of flash flooding in vulnerable areas through late week
