While it may not carry some of the connotations that "ballooning" (growing rapidly as if you were inflating a balloon) or "spiraling" (show a continuous and dramatic increase) have, the DRAE includes "sobrecrecer" > [Sobrecrecer][1] > > Exceder en crecimiento o crecer excesivamente. As an advantage, it is one word. > [...] la sobrecrecida deuda pública > > [...] la **sobrecreciente** deuda pública [1]: https://dle.rae.es/sobrecrecer?m=30_2