That should be the only answer. Helcaraxe wasn't an ice field. It was a frozen ice pack that served as a frozen bridge between Valinor and Beleriand, until the end of the first age.
The Helcaraxe aren't an ice field, they're an ancient region of grinding ice. If you could clarify that would be great, as they were located northwest of Beleriand, which sunk beneath the sea and thus are not really north of Middle Earth anymore.