Cryokinesis

Cyrokinesis is the ability to control and manipulate ice. It can be presumed that any child of Boreas or Khione would have cyrokinesis and that any child of Poseidon/Neptune may also have this power to a lesser degree, since Poseidon is the god of the sea.

The Lost Hero
When first arriving at Boreas' palace in Quebec, Khione introduces herself to the demigods as the goddess of snow and winter. She first shows her power when Piper McLean and Jason Grace try to hold hands; when she sees this, she causes their hands to become so cold, it felt like they were being burned. Later, while flying through a snow storm over Detroit, the wiring in Festus' head becomes frozen. Leo Valdez notes that there is no way this could have happened naturally as it would be too hot for ice to form, but doesn't make the connection with Khione. Later, when the Hunters were defending the Wolf House from a pack of wolves and the Earthborn, Khione arrives on the scene and freezes most of the Hunters, including Thalia Grace.

The Son of Neptune
Blowing a freezing cold wind, a Hyperborean Giant in Alaska turns dozens of griffins into "feathery Popsicle sticks" when Percy Jackson, Hazel Levesque, and Frank Zhang take refuge under his thighs to escape them.

Percy manages to show the ability of cryokinesis to a degree as shown when he manipulates the ice and snow around him to make an 'ice hurricane' that he uses to fight off the Shades created by Alcyoneus.

Abilities
The full range of cyrokinesis are unknown; however, the general extent of these powers are:
 * The ability to create or summon blizzards and hailstorms.
 * It is possible that you can fly or levitate.
 * Project jets of swirling ice and snow from one's hands.
 * Can make icy winds blow something out of the air.
 * Turn yourself into anything associated with snow.
 * Freezing people and objects.
 * Likely immunity to cold.
 * In The Lost Hero, Khione created a "nuclear blast" made of pure cold and ice as oppose to radiation and heat of a regular nuclear explosion.

Users of Cryokinesis

 * Boreas
 * Khione (mostly snow)
 * Hyperboreans
 * Calais & Zethes
 * Alabaster C. Torrington (through Incantare: Gelu Semita)
 * Percy Jackson (limited)
 * Poseidon/Neptune