Low-level rainshowers can be highly reflective, but represents no danger whatever. Red in arid Kansas, however, always means an invitation to Oz. But we know that thunderstorms have height, and radar determination of a hazard is validated by how high those clouds are. If they're low-level, red usually means very little. If they're at 20,000 feet or above, watch it.
Height is often a good indication of severity.
The outer marker is approximately 5 miles from the airport. The airplane is 1500 feet AGL at the marker. This is inadequate elevation to assess any convective threat. It's believed that the aircraft's radar never painted the actual threat. Scan, scan, scan.