A sundog dazzles the sky over Deer Valley on Monday, November 1, 2025. Photo: @alpine.airtime // Aaron Simmons

PARK CITY, Utah – An impressive sun dog shimmered over Deer Valley on Monday, creating a glowing halo that stopped people and staff in their tracks.

Sun dogs — technically called parhelia — form when sunlight passes through millions of tiny, hexagonal ice crystals suspended high in the atmosphere. When those crystals are aligned just right, they refract the light and produce bright patches or full rings on either side of the sun, often mistaken for a second or third sun.

Winter in the Wasatch is prime time for catching the phenomenon, but early-season snowmaking can give nature an extra assist. While the machines don’t create sun dogs, the fine mist of ice crystals they release can boost the number of particles in the air, making the optical effect more vivid and more likely to appear.