Short answer: no
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There is no difference in meaning.

Long answer: just a little bit, with an ambiguity
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1. One of the meanings of **rise** that applies to a immobile, unchanging physical object (like a hillside) is to extend from ground level upward.

2. That's also one of the meanings of the phrasal verb **rise up** in the same context.

3. **Ahead** in this context means in front of you, or that you are traveling toward the hillsides. It doesn't suggest anything about the distance to the hillsides.

4. **Up ahead** is a phrasal preposition that means the same thing, but usually suggesting that the object of the preposition is not far ahead.

So, a listener could hear the sentence as **rising up** + **ahead of us** or as **rising** + **up ahead of us**. But in this sentence, both interpretations come out to mean the same thing.

However, even though **up** is part of a phrasal verb or a phrasal preposition, its meaning as an individual word still influences the listener's imagination. If the listener hears **rising up** as the verb, the version with **up** suggests that the hillsides have a steeper slope than the version without **up**. If the listener hears **up ahead** as the preposition, the version with **up** might suggest that the hillsides are closer than the version without **up**. 

The differences are very subtle, though. I think I could even hear the **up ahead** interpretation as suggesting that the hillsides are far ahead.