What does "Move up-slope" mean in this context?

If near a stream or river, be aware of rising water and possible mudflows in low-lying areas. Move up-slope as quickly as possible.
Source: Key Facts About Protecting Yourself During a Volcanic Eruption, CDC.

  • 2
    It means move uphill, or move to higher ground. You could say it means: Get out of the ditch!
    – J.R.
    May 6, 2015 at 21:58
  • I haven't heard up-slope used in this context. We would generally say "move to higher ground". But the meaning is obvious in context.
    – user3169
    May 6, 2015 at 21:59
  • @user3169 - I've seen this phrase used on occasion. If you search for "move up slope" on Google or Google books, you can find some hits, (like this one, about horseshoe crabs: By instinct, they move up-slope, out of the sea, onto the beaches; or this one, about air movement: In mountainous terrain there is a tendency for air to move up-slope during the day and to drain down-slope during the night). Though its meaning may be obvious, it's still quite an unusual (and interesting) wording – one we don't run across very often. I'm hoping someone will talk about it some more in an answer.
    – J.R.
    May 6, 2015 at 22:05
  • so is there any alternative phrase that has the same meaning and it is commonly used?
    – Maher
    May 6, 2015 at 22:16
  • 1
    @Maher I don't have a good explanation at the moment, but this might help: think of up-slope like uphill, e.g. [The sidestep helps] a skier move uphill or downhill along the fall line through narrow, steep sections of a trail or very deep snow where no other technique is possible. It's just that up-slope has a wider range of use because the slope doesn't have to be a hill. May 6, 2015 at 22:26

1 Answer 1


In this context, 'up-slope' is a synonym for 'uphill'. The higher you are from the banks of the stream, the less likely any mudflow or flood could overwhelm you.

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