This allowed the partly molten , high-pressure gas- and steam-rich rock in the volcano to suddenly explode northwards toward Spirit Lake in a hot mix of lava and pulverized Destroying older rock , overtaking Motion the avalanching face .

Occupying defensive Defending positions throughout the lava beds south of Tule Lake ( in present-day Lava Beds National Monument ) , those few warriors resisted Defending for months the more numerous United States Army forces sent Sending against them , which were reinforced Cause_change_of_strength with artillery .

The Modoc fled Escaping back to the lava beds .

The US Army forces tried to dislodge Removing the Modoc from the natural fortress , now called Request Captain Jack 's Stronghold , in the lava beds along the south shore of Tule Lake in northeastern California .