Fan and Mortar Pictures

This picture taken by Ralph Taylor shows the explosive start of an eruption of Fan and Mortar.

This picture, also taken by Ralph Taylor, focuses on Upper Mortar Geyser.

This picture, taken by Mike Newcomb, focuses on Fan Geyser.

This picture, also taken by Mike Newcomb, focuses on the Upper and Lower vents of Mortar Geyser.

This picture shows a "Lower Mortar Minor" eruption. These eruptions only involve Lower Mortar and "Bottom" (or Arch) Vent. The eruption can reach up to 25 feet though 10 to 15 feet is more normal. They usually last just a few minutes. Historically, Fan and Mortar are known to have erupted independently but for the past few decades this type of activity has not been seen. It was a complete surprise in 1997 when Lower Mortar started having these solo eruptions. The eruption, while not tall, produces a large runoff.