"Yelper." A giantess, daughter of Geirröðr, and the sister of Greip. In the skaldic poem Þórsdrápa by Eilífr Goðrúnarson, and retold by Snorri Sturluson in Skáldskaparmál, she attempts to hinder Thor on his way to her father's stronghold.
During Thor's crossing of the Vimur, the river waxed so greatly that it broke high upon his shoulders. Thor then sees Gjálp standing in certain ravines, one leg in each, spanning the river. Her urinating causes the waters to swell, and he stops her by throwing a huge rock at her.
When Thor arrives at Geirröðr's stronghold he is taken to a goat shed with a single seat. As he sits down he becomes aware that the seat is moving up toward the roof. He thrusts the staff Gríðarvölr up against the rafters and pushes back hard against the chair. Suddenly there is a great crash, followed by terrible screaming: Gjálp and Greip had been beneath the seat and he had broken both their backs.
The name of Gjálp appears in Völuspá hin skamma as one of nine giant mothers, possibly of Heimdallr. The name is also found in the list of troll-wives in the Nafnaþulur. In a verse by Vetrliði Sumarliðason, Thor is said to have stood on lifeless Gjálp.
- Skáldskaparmál, 4, 18.
- Völuspá hin skamma, 7-9.