The Goodall cutoff, developed in Idaho in 1862, kept Oregon bound travelers away from much of the native trouble nearer the Snake River. Other trails were developed that traveled further along the South Platte to avoid local Native American hot spots. Other common causes of death included hypothermia, drowning in river crossings, getting run over by wagons, and accidental gun deaths. Later, more family groups started traveling, and many more bridges and ferries were being put in, so fording a dangerous river became much less common and dangerous. Surprisingly few people were taught to swim in this era. Being run over was a major cause of death, despite the wagons' only averaging 2–3 miles per hour. The wagons could not easily be stopped, and people, particularly children, were often trying to get on and off the wagons while they were moving—not always successfully. Another hazard was a dress getting caught in the wheels and pulling the person under. Accidental shootings declined significantly after Fort Laramie, as people became more familiar with their weapons and often just left them in their wagons. Carrying around a ten-pound rifle all day soon became tedious and usually unnecessary, as the perceived threat of natives faded and hunting opportunities receded. A significant number of travelers were suffering from scurvy by the end of their trips. Their typical flour and salted pork/bacon diet had very little vitamin C in it. The diet in the mining camps was also typically low in fresh vegetables and fruit, which indirectly led to early deaths of many of the inhabitants. Some believe that scurvy deaths may have rivaled cholera as a killer, with most deaths occurring after the victim reached California. Miscellaneous deaths included deaths by childbirth, falling trees, flash floods, homicides, kicks by animals, lightning strikes, snake bites, and stampedes. According to an evaluation by John Unruh, a 4 percent death rate or 16,000 out of 400,000 total pioneers on all trails may have died on the trail. Reaching the Sierra Nevada before the start of the winter storms was critical for a successful completion of a trip. The most famous failure in that regard was that of the Donner Party, whose members struggled to traverse what is today called Donner Pass, in November 1846. When the last survivor was rescued in April 1847, 33 men, women, and children had died at Donner Lake; with some of the 48 survivors' confessing to having resorted to cannibalism to survive. Disease was the biggest killer on the Oregon Trail.