易发程度 有效降雨量 | I级易发区 | II级易发区 | III级易发区 |
Pz = P24 h≥ 50 mm | I | II | III |
Pz = P6 h ≥ 25 mm | II | III | IV |
Pz = P1 h≥ 20 mm或Pz = P3 h ≥ 25 mm且 Pz = P24 h ≥ 30 mm | III | IV | V |