Snowstorms and rainstorms are important contributors to avalanche danger. The temperate level experiences rainstorms, hailstorms, and fog. The latest satellites monitor bad weather around the clock, particularly convective rainstorms, thunderstorms and hailstorms. Severe thunderstorms are often in the spring with rainstorms prevalent during summer evenings. In lower elevations, regional rainstorms and intense thunderstorms can cause flooding in summer and fall. It was naturally vulnerable to flooding by hurricane storm surges and heavy rainstorms. Occasionally, heavy rainfall and rainstorms strike the island. Even during the rainy season precipitation tends to be concentrated in large rainstorms. In fall, cold fronts bring in rainstorms and flooding is not uncommon. Service on the subway system is occasionally disrupted by flooding from rainstorms, even minor ones. Summers in Yaroslavl are typically wet with some heavy rainstorms. In California, there are many rainstorms that runoff into the ocean. This makes the exposed soil more vulnerable to erosion during rainstorms. The Indian region of Assam on was hit by severe rainstorms due to Mora. Two of the top ten deadliest rainstorms ever recorded passed through Lofoten.