She had started life as a Maritime Commission cargo ship called Marco Polo, built by the North Carolina Shipbuilding Company in Wilmington. On November 10, 1943 - exactly one year before she would destroy herself - the Navy renamed her for the Cascade volcano in Oregon, conversion to her new purpose handled by the Norfolk Navy Yard. Commissioning came on July 1, 1944. After a brief shakedown in Chesapeake Bay she loaded munitions at Norfolk, transited the Panama Canal on August 27, and ran independently via Finschhafen to Seeadler Harbor, arriving September 22. Her job was simple: hand out ammunition and explosives to the warships preparing to invade the Philippines.

Standard procedure for an ammunition ship was to moor well away from other vessels - far out in open water where a worst-case detonation would mostly hurt empty sea. Mount Hood was not moored that way. She lay at Berth 380 in the central harbor, near the entrance. The logic was convenience: the berth offered calmer water, shorter boat rides for men transferring ammunition, and enough room for cruisers to come directly alongside for loading. On the morning of November 10, all five of her hatches stood open. 500-pound bombs were being lowered into Number 3 Hold. Around her decks lay 100-pound bombs, powder charges, machine-gun cartridges in three calibers, aerial depth charges, and rocket motors. In total she held roughly 3,800 tons of explosives. Small craft and landing barges clustered along her sides.

The first blast at 08:55 sent flame and smoke above masthead height from amidships. Within seconds, the rest of her cargo detonated. The second explosion was the larger of the two. A mushroom of smoke obscured the harbor for hundreds of yards in every direction. When it cleared, Mount Hood was not there. The seabed where she had floated showed a trench - reports put it at roughly 300 feet long, 50 feet wide, and 30 to 40 feet deep. The largest recognizable piece of her hull was found in that trench, and it was not large. Of her approximately 350 men aboard, and the boat crews alongside her, no human remains were ever recovered. A few pages from a signal notebook floated several hundred yards off, tattered. That was what came back.

The blast tore through the anchorage. Twenty-two smaller craft were sunk or damaged beyond repair. USS Mindanao, a repair ship lying broadside-on about 350 yards away, took the worst of it. Every man on her topside was killed outright. Metal fragments from Mount Hood penetrated Mindanao's side plating and killed or wounded dozens below decks. Mindanao lost 82 of her own crew. In a small irony that made the whole thing even harder, the only Mount Hood crewman ever positively identified was a man who had been working aboard Mindanao at the moment of the explosion. Nine LCM landing craft and a pontoon barge moored alongside Mount Hood were destroyed outright. Add the wounded from other damaged ships to the 432 dead and the total casualty count reached 803. The official investigation, convened within days, could never determine what had set it off.

Mount Hood was struck from the Naval Register on December 11, 1944, little more than a month after she vanished. The charges against the two men who had been headed for the brig were quietly dropped - they were suddenly the luckiest defendants in the fleet. The West Loch disaster that May in Pearl Harbor and the Port Chicago explosion in California that July had already shown how fragile the ammunition-handling system could be. Mount Hood became the third catastrophe in a single year, and the worst loss of Navy life in the Pacific outside combat. The men she took with her were cooks and gunner's mates and seamen, fathers and sons and fiancés. The Navy put their names on rolls of honor and kept their ship's name on a second AE-11 that served later. But what happened in Seeadler Harbor that morning was, and remains, a wound the service was never quite able to explain.