Valley of Ten Thousand Smokes The ash-filled valley covers a area. The ash can be up to deep. In places deep canyons have been cut by the River Lethe, allowing observers to see the ash flow strata. Since the ash has cooled, most of the fumaroles are now extinct and despite its name the valley is no longer filled with 'smoke' (i.e. steam). Vegetation still does not grow in the valley. The signs of volcanic activity are still visible on nearby hills. Katmai's most recent eruption was in 1927, but there have been non-eruptive events as recent as 2003. The Alaska Volcano Observatory still monitors
Geology of the Death Valley area laterally over the surface, laying down cobbles, sand, and mud. Outcrops of the resulting conglomerates, sandstone, and mudstone of the Titus Canyon Formation can be observed in road cuts at Daylight Pass on Daylight Pass Road, which becomes State Route 374 a short distance from the pass. Several other similar formations were also laid down. Large volcanic eruptions, originating near the Nevada Test Site, covered the Death Valley area and much of Nevada in thick sequences of silica-rich ash 27 million years ago. The ash has a rhyolitic composition, which is the volcanic equivalent of the plutonic rock granite; it