3 minutes: air and bleeding control Airway, oxygen, smoke, CO, severe bleeding, and immediate medical organization. 3 hours: shelter and exposure Cold, heat, wet clothing, wind, flood, storm exposure, and unsafe siting. 3 days: water Stored water, source water, purification, testing, hygiene, and pump failure. 3 weeks: food and nutrition Calories, protein, fats, micronutrients, rotation, preparation water, and morale. Long-duration: systems and morale Power, waste, communications, monitoring, medical, spare parts, maintenance, and operator fatigue.