As the ashes erupted from the tower's pinnacle, red, white, blue and green fireworks lit up the sky late on Saturday over Thompson's home for nearly 10 minutes as the crowd cheered. The actual blasts with the ashes took about 30 seconds.
"I'll always remember where I was when Hunter was blown into the heavens," Thompson's neighbor Rita Sherman said.
The 15-story tower, shrouded by tarps for days, was modeled after Thompson's logo: a clenched fist, made symmetrical with two thumbs, rising from the hilt of a dagger. It was built between his home and a tree-covered canyon wall, not far from a tent filled with merrymakers.
"He loved explosions," explained his wife, Anita
Whisky fuelled celebration
The shells were scheduled to be launched on Saturday night from a 45-metre-tall monument erected behind Thompson's house in Woody Creek, just outside Aspen.
The event will be private, open to about 250 invited guests including Thompson's longtime illustrator, Ralph Steadman, and actors Sean Penn and Johnny Depp.
"We haven't noticed a lot of curiosity seekers or pilgrims, but the buzz and the excitement is increasing every hour," family spokesman Matt Moseley said on Friday.
Sean Penn will be one of the
guests at the party
"People are coming into town, people invited to the event, and I've been getting calls from fans who'll say things like 'I'm coming in from Wisconsin with a case of Chivas."
The scotch whisky was a favourite of Thompson's.
The counterculture writer fatally shot himself six months ago in his home at the age of 67. Friends and family have said Thompson was run down by pain and physical problems including hip-replacement surgery and a broken leg.
Thompson is credited with helping pioneer New Journalism - or, as he dubbed his version, gonzo journalism - in which the writer made himself an essential component of the story.
His most famous work is Fear and Loathing in Las Vegas, a wild, sprawling satire featuring "Dr Thompson", a snarling, drug- and alcohol-crazed observer and participant.
His widow, Anita Thompson, 32, has said she plans to publish at least three new books of her late husband's unpublished letters and stories and is looking for a permanent archive for his works.
She has said she doesn't want Saturday's farewell to be a solemn event. She said the memorial will include some reminiscence, readings from Thompson's work and performances by both Lyle Lovett and the Nitty Gritty Dirt Band.
She said Depp, who grew close to Thompson after portraying him in the 1998 film version of Fear and Loathing, funded much of the celebration.
"We had talked a couple of times about his last wishes to be shot out of a cannon of his own design," Depp said. "All I'm doing is trying to make sure his last wish comes true. I just want to send my pal out the way he wants to go out."