Findings and research questions
Findings from published Heimdall Research data. Each one links to the rows behind the number.
Dataset · 5 findings
Arctic Open-Water Window
Not for navigation. Use at your own risk. Provided as is, without warranty of any kind.
Trends
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Vilkitsky Strait: 6 open days a year then, 83 now
At Vilkitsky Strait, mean open days at the 15 percent ice cutoff rose from 5.8 days a year in 1979-1988 to 82.6 days in 2016-2025 (difference +76.8 days).
Breakdown
For Vilkitsky Strait (nsr-vilkitsky), the mean of open_days_15 on full seasons with a numeric value is 5.8 in 1979-1988 (n=9) and 82.6 in 2016-2025 (n=10). That is a rise of 76.8 days. Seasons with a blank open_days_15 are skipped. An open day is a day when average sea-ice concentration inside the gate polygon sits below the 15 percent cutoff.
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Bering Strait is open 53 more days a year than it was
At Bering Strait, mean open days at the 15 percent cutoff rose from 143.2 days a year in 1979-1988 to 196.5 days in 2016-2025 (difference +53.3 days).
Breakdown
For bering-strait, mean open_days_15 on full seasons with a numeric value is 143.2 in 1979-1988 (n=8) and 196.5 in 2016-2025 (n=10). The difference is +53.3 days. Seasons with a blank open_days_15 are skipped.
Places
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A typical year at Bering Strait has 173 open days
Over 45 full seasons (1979 to 2025), Bering Strait had a median of 173 open days at the 15 percent cutoff (range 118 to 234).
Breakdown
The gate_trends row for bering-strait at threshold 15 reports median_open_days 173.0 over 45 seasons (2 excluded). Across non-blank open_days_15 values in gate_seasons, the range is 118 to 234.
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Barrow Strait, Canada: 11 open days a year in 1979-1988, 51 in 2016-2025.
At Barrow Strait, mean open days at the 15 percent cutoff rose from 11.1 days a year in 1979-1988 to 51.3 days in 2016-2025 (difference +40.2 days).
Breakdown
For nwp-barrow, mean open_days_15 on full seasons with a numeric value is 11.1 in 1979-1988 (n=9) and 51.3 in 2016-2025 (n=10). The difference is +40.2 days.
Extremes
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Vilkitsky Strait stayed shut in 8 early years. It opened every year from 2016 through 2025.
Vilkitsky Strait had 8 seasons with zero open days in 1979-1988 and 0 such seasons in 2016-2025.
Breakdown
In 1979-1988, 8 full seasons at nsr-vilkitsky have open_days_15 equal to zero. In 2016-2025, that count is 0. Blank open_days values are not counted as zero.
Dataset · 5 findings
Storm Blackout and Restoration
Estimates from public records and satellite night light. Not for real-time emergency response or for any decision about one address or property.
Trends
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After Irma, the typical county reached 90% of customers restored in 53 hours.
For Irma, the median county hours to 90 percent restored is 52.9 hours (280 counties with a numeric value).
Breakdown
For AL112017, the median of numeric hours_to_90pct_restored is 52.9 hours across 280 counties. Blank and non-numeric cells are left out. A row with reporting_drop true stays in the median when the hour cell is numeric.
Places
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After Maria, night-light brightness took 121 days to return to the usual range in the typical county.
For Maria (AL152017), the median of days_to_normal is 121 days across 46 counties with a value. This column is satellite night-light brightness.
Breakdown
In the county summary table for AL152017, the median of days_to_normal is 121 across 46 counties with a value. days_to_normal counts days of satellite night-light brightness. It is separate from utility hours_to_90pct_restored.
Extremes
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Irma has the largest sum of county outage peaks among these 672 storm events: 8.9 million.
Among these 672 storm events, Irma (AL112017) has the largest sum of county peak customers out: 8,867,374 across 329 counties with a numeric peak. Each county contributes its own peak. Those peaks are not one simultaneous count of customers out.
Breakdown
Summing numeric peak_customers_out for event_id AL112017 gives 8,867,374 across 329 counties. That sum is the largest among the 672 storm events. Each county contributes its own peak. Those peaks are not one simultaneous count of customers out. The next sums are Helene 5,911,300, DR-4586 5,214,663, Ian 3,981,026, and Milton 3,736,269.
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Milton's sum of county outage peaks ranks fifth: 3.7 million.
Milton (AL142024) sums to 3,736,269 peak customers across 51 counties (5th largest sum). Each county contributes its own peak.
Breakdown
For AL142024, the sum of numeric peak_customers_out is 3,736,269 across 51 counties. That ranks 5th, behind Irma, Helene, DR-4586, and Ian. Each county contributes its own peak. Those peaks are not one simultaneous count of customers out.
Method checks
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44 of 672 storm events are tropical cyclones or typhoons.
These 672 storm events include 36 with kind tropical and 8 with kind typhoon (44 together). Kind tropical includes hurricanes. Other counts: severe storms 347, floods 186, tornadoes 24, ice storms 21, winter storms 21, snowstorms 20, straight-line wind 6, coastal storms 3.
Breakdown
Counting kind on storms.csv yields the mix above. The three largest summed county peaks are Irma, Helene, and DR-4586. Kind tropical includes hurricanes.
Dataset · 4 findings
Western Terminal Lakes
Not for water-rights, legal or engineering decisions.
Places
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Great Salt Lake's south arm: July open water was 12% lower in 2026 than in July 2019.
Great Salt Lake south arm open-water area fell from 2017.2 km2 in July 2019 to 1770.6 km2 in July 2026 (loss 246.5 km2, 12.2 percent).
Breakdown
For great-salt-lake-south, water_area_km2 is 2017.2 in 2019-07 and 1770.6 in 2026-07. That is a loss of 246.5 km2, or 12.2 percent of the July 2019 area. This compares July 2019 with July 2026. July water_area_km2 values are 2019 2017.2; 2020 1968.7; 2021 1816.8; 2022 1743.3; 2023 1919.5; 2024 1956.3; 2025 1829.1; 2026 1770.6. Low-confidence Julys: none.
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Great Salt Lake's north arm: July open water was 16% lower in 2026 than in July 2019.
Great Salt Lake north arm open-water area fell from 1369.9 km2 in July 2019 to 1149.3 km2 in July 2026 (loss 220.6 km2, 16.1 percent).
Breakdown
For great-salt-lake-north, water_area_km2 is 1369.9 in 2019-07 and 1149.3 in 2026-07. The loss is 220.6 km2, or 16.1 percent. This compares July 2019 with July 2026. July water_area_km2 values are 2019 1369.9; 2020 1350.3; 2021 1169.2; 2022 1181.5; 2023 1228.2; 2024 1203.7; 2025 1231.6; 2026 1149.3. Low-confidence Julys: none.
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Salton Sea: July open water was 9% lower in 2026 than in July 2019.
Salton Sea open-water area fell from 850.4 km2 in July 2019 to 772.0 km2 in July 2026 (loss 78.3 km2, 9.2 percent).
Breakdown
For salton-sea, water_area_km2 is 850.4 in 2019-07 and 772.0 in 2026-07. The loss is 78.3 km2, or 9.2 percent of the July 2019 area. This compares July 2019 with July 2026. July water_area_km2 values are 2019 850.4; 2020 840.5; 2021 842.1; 2022 824.1; 2023 811.4; 2024 814.2; 2025 792.6; 2026 772.0. Low-confidence Julys: none.
Extremes
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Lake Abert: July open water was 7% lower in 2026 than in July 2019.
Lake Abert open-water area fell from 128.0 km2 in July 2019 to 119.5 km2 in July 2026 (loss 8.5 km2, 6.7 percent).
Breakdown
For lake-abert, water_area_km2 is 128.0 in 2019-07 and 119.5 in 2026-07. That is a loss of 8.5 km2, or 6.7 percent. This compares July 2019 with July 2026. July water_area_km2 values are 2019 128.0; 2020 110.0; 2021 81.7; 2022 136.4; 2023 110.1; 2024 129.6; 2025 131.8; 2026 119.5. Low-confidence Julys: 2022, 2023. An earlier published table for these two Julys showed a gain. This table shows a loss.
Provided as is, without warranty of any kind.