The Weekly Volcanic Activity Report: December 17-23, 2025
New activity/unrest was reported for 4 volcanoes from December 17 to 23, 2025. During the same period, ongoing activity was reported for 19 volcanoes.
Strong and shallow M6.0 earthquake hits Taiwan
A strong and shallow earthquake registered by the USGS as M6.0 hit near Yujing, Taiwan, at 09:47 UTC (17:47 local time) on December 24, 2025. The agency reported a depth of 10 km (6.2 miles), while EMSC reported M6.0 at a depth of 12 km (7.4 miles). There is no tsunami threat from this earthquake.
Kīlauea enters eruptive episode 39 exactly one year into ongoing summit eruption, with lava fountains rising over 420 m (1 400 feet)
Kīlauea entered eruptive episode 39 at 20:10 HST on December 23, 2025 (06:10 UTC on December 24) as lava fountains rose from twin vents on the floor of Halemaʻumaʻu crater. Within about 95 minutes, fountain heights increased from 10 m (30 feet) to more than 420 m (1 400 feet), with lava flows covering 10–20% of the crater floor by 21:14 HST and a plume reaching 6 000 m (20 000 feet).
Wild Turkey Fire fully contained, evacuation order lifted for Fourmile Canyon, Colorado
A wildfire ignited west of Boulder, Colorado, in Fourmile Canyon at around 17:50 local time (LT) on December 22, 2025, triggering evacuation orders for residents near Wild Turkey Trail. Firefighters contained the roughly 1.6 ha (4 acres) blaze before midnight, allowing officials to lift evacuation orders in the area.
Rare High Risk (4/4) for excessive rainfall issued for Southern California
The NWS Weather Prediction Center has issued a rare High Risk (level 4/4) for excessive rainfall across Southern California from Wednesday, December 24, through the morning of Thursday, December 25. 2025.
Extremely dangerous marine conditions across coastal California waters this week
Extremely dangerous marine conditions are developing across Northern and Central California waters this week, the National Weather Service (NWS) San Francisco Bay Area warned on Tuesday, December 23, 2025. Storm Force winds are forecast across the coastal waters with Gale Force winds extending into San Francisco and Monterey bays beginning Tuesday morning. Seas are expected to build to near 6 m (20 feet) under the strongest winds, posing life-threatening conditions for mariners.
Winter Storm Warnings across Sierra Nevada, White Mountains, and northern California
Winter Storm Warnings are in effect across parts of California from late December 23 through December 27, 2025, as a strong atmospheric river moves inland, bringing heavy mountain snowfall and high winds.
Strong atmospheric river to bring heavy rain, snow, and flooding to California this week
A strong atmospheric river is forecast to impact California from December 23 to 27, 2025, bringing widespread heavy rainfall, flash flooding, and high-elevation snow. The system is expected to produce 250 to 500 mm (10–20 inches) of precipitation in parts of the Sierra Nevada and 150 to 300 mm (6–12 inches) in the Coast and Transverse Ranges. The National Weather Service has issued high-risk alerts for flash flooding across southern California and moderate winter storm impacts over the Sierra Nevada.
Snow blankets Saudi Arabia’s deserts for first time in 30 years
A rare widespread snowfall event affected northern Saudi Arabia in December 2025, transforming desert landscapes and mountain ranges across Tabuk and Hail into snow-covered terrain. The snowfall occurred as a sharp cold air intrusion lowered temperatures below freezing at higher elevations, with snow settling near 2 600 m (8 530 feet) and surface temperatures reported near −4°C (25°F), according to regional media reports. Such widespread snowfall over desert areas is considered exceptionally uncommon for the region.
Floods, heavy snow, and blizzards kill at least eight across 25 provinces in Iran
At least eight people have died after heavy snow, floods, and blizzards affected more than 25 provinces in Iran between December 15 and 21, 2025, according to the Iranian Red Crescent Society.
