Cauac, also written Kawak, is Kawoq in K'iche', and the sign is the storm. The Classic glyph carries a bunched cluster of markings that epigraphers also read as stone, so the sign stands both for the rain-bearing cloud and for the living rock, which in Maya thought are not far apart since the rain is understood to be held in the mountain.
Central Mexico places Quiahuitl, rain, in the nineteenth position, agreeing with the storm reading. In both traditions the sign belongs with the rain deities, Chaak among the Maya and Tlaloc in central Mexico, and with the thunder that announces the season on which the maize depends.
Cauac is a Year Bearer in the Postclassic Yucatec system Diego de Landa recorded, whose four permitted openers of a Haab year are Kan, Muluc, Ix and Kawak. It is not one of the Classic four, Ik, Manik, Eb and Kaban, nor one of the four used by the highland communities that keep the count today. In K'iche' practice Kawoq is connected with the community and with the midwife, and, as with all these readings, the atlas records what the tradition holds rather than offering it as counsel.
The nineteenth sign carries a further association through the Haab, whose five-day closing period, Wayeb, is a time of danger in the colonial accounts precisely because the year is between bearers. Storm and stone, cloud and mountain, are the images the sources reach for when describing that interval, and Cauac belongs to the same group of ideas without being confined to it.