[thackney]

The area the road sits on is quite flat. It would not be all past the road but a lot of it would be on the road.

Looking down from the debris flow:

[DuncanWaring]

Three possibilities:

1. It stops before the road - no problem.
2. It stops just past the road - dig it out.
3. It speeds up to 10 meters per day (your conjecture) - within a few months, it’s finished flowing - dig it out.