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
Washington State Route 10 was co-signed with US 10 and US 97 during the creation of the United States Numbered Highways in 1926. State Road 3 became PSH 3 during the creation of the primary and secondary state highways in 1937, still co-signed with US 10 and US 97 through the Yakima River valley. US 10 was temporarily re-aligned over Blewett Pass in the late 1930s, leaving US 97 alone in the Yakima River valley, until US 10 was moved back to its original route in 1946 after US 2 was extended west from Idaho. During the 1964 highway renumbering, US 10 completely replaced