Operation Aloha was an unnamed American operation, which its name having been dubbed by the news press, was enacted on April 28, 1952 by President Harvey McCullen and called for the movement of 170,000 selected American civilians to the Hawaiian Islands, where they would stay indefinitely.
The purpose of the operation was to "preserve the American culture, history and way of life," should the Chimera overrun the United States. The 170,000 civilians were selected by a committee appointed by President McCullen, in which the selection were based on several factors, including engineering, scientific, medical, and agricultural knowledge, as well as genetic diversity.
The Hawaiian Islands were guarded by a naval detachment, consisting of seven battleships, to protect against Chimeran air-strikes. However, critics of "Operation Aloha" were quick to point out that the battleships were also likely intended to turn away refugee vessels from other parts of the world, including from the United States itself.
At 0823 on July 14th, 1953 the USS Providence, which had been sent to resupply the colony, reported that all 172,000 civilians and the crews of the battleships had mysteriously disappeared without a trace after radio contact was lost between Hawaii and the American mainland. The event was preceded months earlier by eyewitness reports of strange astronomical effects which included a glowing fissure seen in the sky which lasted for a few seconds, under which there appeared to be a "second sky," and sightings of unidentified flying objects.
The colony's fate is never expounded upon and an explanation is never even attempted. However, the "strange astronomical effects" described in SRPA Intelligence Memorandum 14 may well be early attempts by the Chimera at opening an wormhole with insufficient power. At this point in the war, the Chimera had not conquered the United States but had several key towers in its possession. Since the towers weren't yet fully activated and the worldwide energy network had yet to be established, the New York tower, the origin point of the wormhole, had an insufficient amount of power and possibly caused a "false start", as it were. Why the fissure in the sky appeared over Hawaii remains a mystery.
It may have just been a hiccup in the Chimera's as-yet-unstable power grid. At the end of Resistance 3, the wormhole was shown to have a modicum of vacuum-like power, sucking in the remains of the New York tower and the terraformer used to destroy it. It is possible that the unstable fissure sucked up the colony, wiping it from existence. This does not, however, explain the disappearance of only the crew on the battleships, rather than the ships themselves. It is possible that the fissure was a stable enough wormhole for either an unknown species of Chimera, or possibly Crawler-infested Spires to slip through, infect the humans stationed there, and return through the fissure, bringing both food and ready-to-be-converted reinforcements to the Chimeran homeworld. The "unidentified flying objects" from the SRPA memorandum may be the vessels used to abducted the 170,000+ human bodies through the void. Whatever the method, a colony of over 170,000 people disappeared. The primary anomaly here is that the disappearance occurred nearly five months after the fissure in the sky. Maybe the Crawlers laid dormant for those months, recuperating from crossing the void and finding themselves in humid, warm climate. They have been known to be capable of overcoming hardened soldiers, so it could be possible the remnants moved the bodies to an interior location on the island.