did humans have any impact on it?
No.
Mount St. Helens
Fifty-seven people were killed during the eruption. Had the eruption occurred one day later, when loggers would have been at work, rather than on a Sunday, the death toll could have been much higher.

who was harry r. truman? He was an American businessman, bootlegger, and prospector. when was he born? October 1896. where is he from? He lived near Mount St. Helens. where is this mount located? Skamania County, Washington, in the Pacific Northwest region of the United States. is it a volcanic mount? Yes. has it ever erupted? Yes. during which period did the mount erupt the first time? The "Ape Canyon Stage". did any tribe live near or on this mount? UNANSWERABLE did the mount erupt in the year 1980? Yes.
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Mount St. Helens [SEP] Human impact from the 1980 eruption
Fifty-seven people were killed during the eruption. Had the eruption occurred one day later, when loggers would have been at work, rather than on a Sunday, the death toll could have been much higher. Eighty-three-year-old Harry R. Truman, who had lived near the mountain for 54 years, became famous when he decided not to evacuate before the impending eruption, despite repeated pleas by local authorities. His body was never found after the eruption. Another victim of the eruption was 30-year-old volcanologist David A. Johnston, who was stationed on the nearby Coldwater Ridge. Moments before his position was hit by the pyroclastic flow, Johnston radioed his famous last words: "Vancouver! Vancouver! This is it!" Johnston's body was never found.