Occasional warm days in winter are critical for honey bee survival; dysentery problems increase in likelihood during periods of more than two or three weeks with temperatures below 50 °F (10 °C). When cleansing flights are few, bees are often forced out at times when the temperature is barely adequate for their wing muscles to function, and large quantities of bees may be seen dead in the snow around the hives. Colonies found dead in spring from dysentery have feces smeared over the frames and other hive parts.