Rashi on Exodus 15:11/רש"י על שמות ט״ו:י״א

1באלם means AMONGST THE MIGHTY, just as (Ezekiel 17:13) “and the mighty of (אילי) the land he took away”; (Psalms 22:20) “O, thou my strength (אילותי) hasten to my help”.

2נורא תהלות means Thou art an object of dread so that people do not recount thy praises fearing lest these may be enumerated less then they really are, just as it is written (Psalms 65:2) “To Thee, silence is praise”.