Yes, UMBEL is a Scrabble word!

Letter values in Scrabble US: U 1, M 3, B 3, E 1, L 1.

Is it a valid word?

UMBEL is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

flat-topped or rounded inflorescence characteristic of the family Umbelliferae in which the individual flower stalks arise from about the same point; youngest flowers are at the center