{
 "method": "expected keel-depth hazard area (sum of P(shoal<10.5 m) over unseen navigable cells) per ship-day, within shipping-relevant water",
 "relevance": "within 30 km of the Churchill route or an NRCan Canadian shipping route / Arctic sea route, or 15 km of a sealift community; blocks where the gravity prior fails (inland lakes) excluded",
 "hazard_field": "hazard_nat_v2 (coast-aware head, 2026-09-06)",
 "top20": [
  {
   "lon": -79.5,
   "lat": 56.0,
   "area_km2": 30,
   "unseen_cells": 4204,
   "expected_hazard_km2": 11.48,
   "ship_days": 0.7,
   "hazards_per_ship_day": 15.338
  },
  {
   "lon": -66.5,
   "lat": 62.0,
   "area_km2": 73,
   "unseen_cells": 14581,
   "expected_hazard_km2": 24.25,
   "ship_days": 1.8,
   "hazards_per_ship_day": 13.251
  },
  {
   "lon": -67.0,
   "lat": 62.5,
   "area_km2": 60,
   "unseen_cells": 12202,
   "expected_hazard_km2": 18.99,
   "ship_days": 1.5,
   "hazards_per_ship_day": 12.664
  },
  {
   "lon": -101.0,
   "lat": 68.5,
   "area_km2": 64,
   "unseen_cells": 20755,
   "expected_hazard_km2": 19.49,
   "ship_days": 1.6,
   "hazards_per_ship_day": 12.218
  },
  {
   "lon": -93.0,
   "lat": 62.0,
   "area_km2": 54,
   "unseen_cells": 10550,
   "expected_hazard_km2": 15.34,
   "ship_days": 1.4,
   "hazards_per_ship_day": 11.347
  },
  {
   "lon": -96.0,
   "lat": 68.5,
   "area_km2": 28,
   "unseen_cells": 8986,
   "expected_hazard_km2": 7.67,
   "ship_days": 0.7,
   "hazards_per_ship_day": 11.044
  },
  {
   "lon": -68.0,
   "lat": 63.5,
   "area_km2": 69,
   "unseen_cells": 14898,
   "expected_hazard_km2": 18.88,
   "ship_days": 1.7,
   "hazards_per_ship_day": 10.939
  },
  {
   "lon": -82.5,
   "lat": 69.0,
   "area_km2": 36,
   "unseen_cells": 12420,
   "expected_hazard_km2": 9.58,
   "ship_days": 0.9,
   "hazards_per_ship_day": 10.612
  },
  {
   "lon": -82.0,
   "lat": 69.0,
   "area_km2": 43,
   "unseen_cells": 14902,
   "expected_hazard_km2": 11.3,
   "ship_days": 1.1,
   "hazards_per_ship_day": 10.423
  },
  {
   "lon": -67.5,
   "lat": 63.0,
   "area_km2": 96,
   "unseen_cells": 20420,
   "expected_hazard_km2": 24.48,
   "ship_days": 2.4,
   "hazards_per_ship_day": 10.172
  },
  {
   "lon": -68.0,
   "lat": 63.0,
   "area_km2": 283,
   "unseen_cells": 60149,
   "expected_hazard_km2": 69.71,
   "ship_days": 7.1,
   "hazards_per_ship_day": 9.863
  },
  {
   "lon": -114.0,
   "lat": 67.5,
   "area_km2": 107,
   "unseen_cells": 32599,
   "expected_hazard_km2": 26.16,
   "ship_days": 2.7,
   "hazards_per_ship_day": 9.769
  },
  {
   "lon": -80.0,
   "lat": 56.5,
   "area_km2": 291,
   "unseen_cells": 41688,
   "expected_hazard_km2": 68.25,
   "ship_days": 7.3,
   "hazards_per_ship_day": 9.376
  },
  {
   "lon": -70.0,
   "lat": 62.5,
   "area_km2": 113,
   "unseen_cells": 23017,
   "expected_hazard_km2": 26.48,
   "ship_days": 2.8,
   "hazards_per_ship_day": 9.348
  },
  {
   "lon": -114.5,
   "lat": 67.5,
   "area_km2": 192,
   "unseen_cells": 58177,
   "expected_hazard_km2": 44.09,
   "ship_days": 4.8,
   "hazards_per_ship_day": 9.184
  },
  {
   "lon": -108.0,
   "lat": 67.0,
   "area_km2": 215,
   "unseen_cells": 61866,
   "expected_hazard_km2": 48.84,
   "ship_days": 5.4,
   "hazards_per_ship_day": 9.097
  },
  {
   "lon": -116.0,
   "lat": 68.5,
   "area_km2": 38,
   "unseen_cells": 12567,
   "expected_hazard_km2": 8.15,
   "ship_days": 0.9,
   "hazards_per_ship_day": 8.631
  },
  {
   "lon": -101.0,
   "lat": 68.0,
   "area_km2": 42,
   "unseen_cells": 13267,
   "expected_hazard_km2": 8.71,
   "ship_days": 1.1,
   "hazards_per_ship_day": 8.272
  },
  {
   "lon": -92.5,
   "lat": 62.0,
   "area_km2": 109,
   "unseen_cells": 21343,
   "expected_hazard_km2": 22.09,
   "ship_days": 2.7,
   "hazards_per_ship_day": 8.133
  },
  {
   "lon": -79.0,
   "lat": 56.0,
   "area_km2": 29,
   "unseen_cells": 4032,
   "expected_hazard_km2": 5.59,
   "ship_days": 0.7,
   "hazards_per_ship_day": 7.789
  }
 ],
 "total": {
  "area_km2": 1972,
  "ship_days": 49,
  "cost_low_MCAD": 5,
  "cost_high_MCAD": 9,
  "expected_hazard_km2": 489.5
 },
 "n_boxes_considered": 1115
}