Mt Blackburn about 10 miles from the base of Muir Glacier apparently “erupted” on April 10, 1902. A geologist, J.C. McFarland who happened to be nearby stated:
“On April 11 at about 7:30 in the morning the air about me became oppressive with a distinct and uncommon silence. In my wanderings through different wilds I had become used to many strange freaks of nature, but this one appalled me. I was in a rough mountainous country, I should judge about 10 miles from the base of Mount Blackburn, in Southeastern Alaska, not far from the starting point of a glacier called Muir Glacier. Suddenly the earth beneath my foot shook, a low rumbling sound accompanied the quaking. I glanced up at Mount Blackburn. Instantly it seemed as though the peak had opened; a cloud of ashes and smoke shot out into the air several hundred feet, and then there seemed to flow from the opening in the top a stream of dirty stuff mixed with large and small boulders. This continued only for about ten minutes then ceased as suddenly as it had begun.
It was three days after many perilous attempts before I succeeded in reaching the base of the mountain. Then I discovered that the country for miles around had been affected. The small undergrowth of the trees had been entirely covered. This stuff which poured from the top of the mountain was not even warm, but seemed to consist purely of dust rocks and other substances. As far as I can discover this mountain had never been considered of a volcanic nature.”
The official story is that the last time Mt Blackburn erupted was 3-5 million years ago. The 1902 incident was probably just a geologic burp.
New York Times, June 3, 1902