Ear Spring

Ear Spring is a hot spring in Yellowstone National Park’s Upper Geyser Basin near Old Faithful that is usually quiet but occasionally erupts like a geyser. In those rare outbursts, it can hurl water, rocks, and debris more than 25 feet for several minutes. A significant eruption on September 15, 2018, lasted about a minute, sent material 20 to 30 feet high, expelled small rocks and long-discarded trash, and killed nearby bacterial mats adapted to cooler water. That activity appeared to be part of a wider thermal shift in the area, as a new feature opened near Pump Geyser and nearby springs also became more active.

Mammoth, Wyoming · United States