HALO techniques are used for missions to prevent detection of the aircraft and the jumpers. Extreme accuracy is required, because the parachutes are deployed at a low altitude. HALO involves paratroopers jumping at around 25,000 feet and freefalling down to 3,500 feet. Plummeting at a terminal velocity of 126 mph, parachutists can descend this distance within two minutes. A HALO jump gets the jumper out of sight in a hurry, and as such, they are less vulnerable. A drawback to this technique is that the jumpers must exit the aircraft over, or close to, enemy territory, thus making the aircraft a potential target for enemy surface-to-air or air-to-air defenses.

Watch as 7th Special Forces Group Green Berets and Chilean sailors conduct high-altitude military parachuting while exiting a C-130H3 during Emerald Warrior, 2015. Emerald Warrior is the Department of Defense’s only irregular warfare exercise, allowing joint and combined partners to train together and prepare for real-world contingency operations.

https://www.youtube.com/watch?v=qlGJBdQYUB8