Which volcano erupted from January 18-21, 1951, causing over 3,000 deaths?

The volcano that erupted from January 18–21, 1951, causing over 3,000 deaths, was Mount Lamington in Papua New Guinea.

Mount Lamington stands in Oro Province, near Popondetta. Before 1951, it was not widely recognized as an active volcano because it was heavily forested and had no known historical eruptions. Small earthquakes and ash emissions began in January, intensifying over several days.

The catastrophic climax came on January 21, when an explosive eruption generated a fast-moving pyroclastic density current—an incandescent mixture of ash, gas, and rock. It swept across roughly 230 square kilometers, destroying settlements including Higaturu. Later investigations estimated 2,942 deaths, commonly rounded to about 3,000.

A common mix-up is treating January 18 as the date of the single deadly blast. Activity had begun by then, but the principal destructive eruption occurred on January 21. The eruption continued intermittently until 1956, while a lava dome grew inside the new crater.