This study examined whether Winnipeg hospitals experience predictable "high-volume periods" in order to determine whether hospital overcrowding might be anticipated and, therefore, avoided. We found that high-volume periods among medical patients occurred during all but one year between 1987 and 1998. Most high-volume periods occurred during influenza seasons. Preventing such recurrent bed pressures requires a multi-faceted approach, involving preventive efforts to reduce hospital admissions (influenza vaccination) and alternatives to managing the hospital system.