It is overwhelming. Overwhelming is an adjective used in Colombia and has the meaning of oppressive, distressing, suffocating, atosigante, hastiante, awkward, boring, oppressor.
Indeed, it is not recognized by the Royal Academy of the Spanish language, the word overwhelming, but overwhelming, which would be the adjective used to define what is overwhelming or that overwhelms. But can exist that qualifying in other languages of speaks Spanish.
overwhelming is incorrectly written and it should be written as "Abrumador" being its meaning: something that overwhelms, that exceeds our possibilities of supporting it.