def melt_fromdebris_func(h, a, k):
    """ Second order reaction rate equation used to estimate melt from debris thickness
    The standard form is 1/A = 1/A0 + kt
      1/b = 1/a + k*h  derived from the standard form: 
    where b is melt, h is debris thickness, and k and a are constants. """
    return 1 / (1 / a + k * h)