1) Become more declivitous 2) Become more inclined 3) Become more precipitous 4) Become more uphill 5) Become precipitous 6) Become steeper 7) Change 8) Get harder to climb 9) Get more precipitous 10) Give a higher grade to 11) Go from 30 to 35 degrees 12) Go uphill fast 13) Increase in verticality 
• (v. i.) To become steep or steeper.
Steep'en intransitive verb [ imperfect & past participle Steepened ; present participle & verbal noun Steepening .] To become steep or steeper. « As the way steepened . . . I could detect in the hollow of the hill some traces...
[v] - become steeper 2. [v] - make steeper
to make or become steeper.