A Slice of America's Volcanic History
Lassen Volcanic National Park had quite a bit of reminders that this year is the 50th anniversary of our nation's Wilderness Act, which is one of our best ideas. However, the national park system itself is often referred to as "America's best idea" and I'm not about to get into which idea was better, but am thankful for both. Lassen is also nearing an anniversary of its own: the eruption of Lassen Peak in May, 1915. There are many reminders of volcanism in the park, and none are as accessible as the Devastated Area. Many serious hikers turn their noses up at the crowds and lack of a "true" wilderness feeling in most national parks, but I'd like to remind them that America belongs to all Americans, and not all of us can pull off a 12-mile-long dayhike. The Devastated Area Interpretive Trail provides an opportunity for even wheelchair-bound visitors to enjoy a little nature, and take a brief trip through the mists of time.
Lassen Peak became active after being dormant for over 27,000 years in May, 1914, but the show didn't begin for another year when glowing blocks of lava were observed tumbling down the mountain's flanks on May 14 1915. A much larger eruption occurred May 19-20, 1915 which saw large volumes of volcanic rock spill down the mountain's northeast side that combined with melting snow to form a quickly moving lahar which ended up in Hat Creek. The fun wasn't over yet as the lahar continued to flow down Lost Creek for 6 miles before finally coming to rest. A massive volume of melted snow continued to surge down to flood the lower end of Hat Creek Valley early on the 20th.
The volcanism was seemingly over when a massive eruption shattered the late-spring calm on the afternoon of May 22. An enormous column of volcanic ash rose over 30,000 feet into the air (giving an alternative illustration of the term "stratovolcano"), and sent an even larger lahar over the same area that was devastated a few days earlier. Volcanic ash blanketed the area northeast of the mountain.
The closest analogue to the Devastated Area that I've seen is the area just east of the San Francisco Peaks. A few scrubby pines cling to life in the nutrient-poor and overly-porous (as far as most trees are concerned) soil, and the lack of cover makes this spot warmer and sunnier than most of the park.
The interpretive trail is only about 1/3 mile, but enjoy the interpretive signs next to the various types of volcanic rock from the 1915 eruption that have been placed alongside the trail.
Check out the Triplogs.