Why do mudflows develop with some volcanic eruptions? ​

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Explanation:

Lahars can also be formed when high-volume or long-duration rainfall occurs during or after an eruption. On steep slopes, rainwater can easily erode and transport fine-grained, loose volcanic sediment and form a slurry, especially if vegetation has not had time to grow back on recent volcanic deposits

answer; gravity pulls glaciers down hill and as glaciers flow it pick up rocks and soil;