On July 2, 1999, at 1400 central daylight time, a Piper J-3C, N3371N, was substantially damaged when it nosed over in an oat field during a precautionary landing. The private pilot reported that she encountered high winds and wind shear and decided to make a precautionary landing to the oat field located four miles northwest of Independence, Iowa. During landing rollout the airplane went up on its nose. The private pilot was not injured. The 14 CFR Part 91 flight had departed Hutchinson Municipal Airport, Hutchinson, Minnesota, en route to the Independence Municipal Airport, Independence, Iowa. Visual meteorological conditions prevailed and no flight plan had been filed. The pilot reported that she encountered severe turbulence and 40 to 50 knots wind gusts about 10 miles from Independence, Iowa. She reported it became difficult to control the airplane. She reported she decided to put the airplane on the ground before she lost all control. The pilot reported the weather conditions that existed near the destination airport had not been forecast when she had checked the weather about 2.5 hours prior to the accident. She reported she attempted to land the airplane in an oat field. She reported the airplane was traveling about 30 mph over the ground when the airplane impacted the oat field. The airplane traveled about 10 feet when the airplane went up on its nose and sustained substantial damage.