{
  "title": "Storm Lake Winter Propane Survival Calculator",
  "author": "Barbara Cintron",
  "location": "Storm Lake, Iowa (Zone 4b)",
  "version": "1.0",
  "citation": {
    "heating_base_temp_F": 65,
    "stormlake_avg_extreme_min_F": -25,
    "propane_energy_content_Btu_per_gallon": 91500,
    "typical_household_daily_consumption_gallons": {
      "mild": 1.2,
      "moderate": 2.8,
      "severe": 5.4
    },
    "blizzard_duration_hours": 72,
    "design_outdoor_temp_F": -30,
    "indoor_setpoint_F": 68,
    "house_envelope_factor": 0.85,
    "notes": "Consumption rates derived from Buena Vista County Cooperative Extension 2024 Winter Energy Survey, adjusted for Zone 4b extremes. House envelope factor accounts for typical 1970s ranch construction insulation degradation."
  },
  "formula": {
    "description": "Propane required = (consumption_rate_gal/day × duration_days) / house_efficiency",
    "variables": {
      "consumption_rate_gal_day": "Function of delta-T between indoor setpoint and outdoor temp",
      "duration_days": "Blizzard event length",
      "house_efficiency": "Envelope integrity multiplier"
    }
  }
}