While on the downwind leg of the traffic pattern, the flight instructor realized that the storm, including heavy rain and possible windshear, had approached the airport more quickly than expected. He noted that the airplane was 300 feet above the pattern altitude, and he told the student to reduce power to descend. The throttle was already at idle power, but the airplane was not descending. As the student turned the airplane onto the base leg, the flight instructor observed a corporate jet execute a go-around before reaching the end of the runway. He then noted that the airplane’s primary flight display indicated that was it descending at 1,500 feet per minute. He then took control of the airplane, added full power, and set a climb attitude. Realizing that they would not be able to land on the runway before the heavy rain and possible windshear conditions arrived, the flight instructor chose to conduct a go-around and turned away from the storm and flew to the southeast at full power with the carburetor heat on. He estimated that the airplane was about 200 feet above ground level when it encountered heavy rain, which reduced the visibility to “virtually 0.” His priority was to keep the wings level with a slight nosehigh attitude to gain altitude. He heard the student pilot say “pull up” about the time that the airplane impacted a plowed field. The flight instructor also stated that there was hail at the time of the accident. The flight instructor reported that there were no pre-impact mechanical malfunctions or failures with the airplane.