Every heat event the pipeline tracked between 2020-05-01 and 2020-09-30, with how each one grew, peaked and moved. Anomalies are against the 1991–2020 baseline.
Season at a glance
Events tracked
27
Total heat burden
93.80 Mkm²·days
Longest
26days (#24)
Hottest
+16.9°C (#7)
With a heat dome
7of 27 events
A heat dome is the stricter object: a tracked heat event with a closed 500 hPa anticyclone whose influence cap overlies it, after Loikith et al. (2026). Most heatwaves are not domes, so the label is a finding and not a synonym.
ERA5 daily maximum 2 m temperature over land, against the 1991–2020 climatology (p90 in a centred 15-day window). A heatwave cell is Tx above p90 on at least 3 consecutive days.
When the events ran
Overlapping bars are concurrent events in different places, not one event counted twice: each is a separately labelled cluster of contiguous heatwave cells.
How each event evolved
Event #24 — 2020-09-05 → 2020-09-30 26 daysheat dome · 14/26 d · Z500 +274 m
peak 2.29 M km² on 2020-09-26 · max +15.1 °C · mean +7.9 °C · burden 23.37 M km²·d · drift 2555 km (42.8 N 19.5 E → 64.6 N 32.0 E)
Event #7 — 2020-06-10 → 2020-06-29 20 daysheat dome · 16/20 d · Z500 +280 m
peak 1.40 M km² on 2020-06-25 · max +16.9 °C · mean +8.3 °C · burden 14.53 M km²·d · drift 44 km (60.2 N 22.6 E → 59.8 N 22.7 E)
Event #23 — 2020-08-28 → 2020-09-21 25 dayshigh on 8/25 d only
peak 1.89 M km² on 2020-09-01 · max +13.9 °C · mean +7.1 °C · burden 12.80 M km²·d · drift 1245 km (40.3 N 27.3 E → 37.7 N 41.4 E)
Event #6 — 2020-06-05 → 2020-06-14 10 daysno overlying high
peak 1.54 M km² on 2020-06-10 · max +11.5 °C · mean +7.6 °C · burden 7.63 M km²·d · drift 1199 km (40.9 N 31.3 E → 47.6 N 43.1 E)
Event #2 — 2020-05-09 → 2020-05-23 15 daysheat dome · 11/15 d · Z500 +210 m
peak 923k km² on 2020-05-16 · max +15.1 °C · mean +7.9 °C · burden 7.11 M km²·d · drift 1970 km (41.1 N 21.6 E → 38.7 N 44.6 E)
Event #17 — 2020-08-05 → 2020-08-18 14 dayshigh on 4/14 d only
peak 1.15 M km² on 2020-08-09 · max +13.6 °C · mean +8.1 °C · burden 6.71 M km²·d · drift 2008 km (42.0 N -5.2 E → 57.1 N 10.3 E)
Event #10 — 2020-06-28 → 2020-07-09 12 dayshigh on 5/12 d only
peak 888k km² on 2020-07-07 · max +13.2 °C · mean +8.4 °C · burden 4.78 M km²·d · drift 1353 km (44.8 N 39.0 E → 56.4 N 44.6 E)
Event #3 — 2020-05-17 → 2020-06-02 17 daysheat dome · 9/17 d · Z500 +221 m
peak 568k km² on 2020-05-22 · max +11.5 °C · mean +6.9 °C · burden 3.03 M km²·d · drift 189 km (43.4 N -4.1 E → 43.6 N -6.4 E)
Event #19 — 2020-08-09 → 2020-08-22 14 dayshigh on 5/14 d only
peak 346k km² on 2020-08-18 · max +9.4 °C · mean +6.4 °C · burden 2.03 M km²·d · drift 640 km (59.3 N 6.8 E → 60.8 N 17.9 E)
Event #13 — 2020-07-23 → 2020-08-02 11 daysno overlying high
peak 194k km² on 2020-07-31 · max +8.9 °C · mean +4.9 °C · burden 1.15 M km²·d · drift 347 km (40.0 N -5.8 E → 38.1 N -2.6 E)
Event #27 — 2020-09-26 → 2020-09-30 5 daysno overlying high
peak 367k km² on 2020-09-29 · max +10.2 °C · mean +6.5 °C · burden 1.13 M km²·d · drift 751 km (40.9 N 32.2 E → 36.6 N 38.9 E)
Event #4 — 2020-05-25 → 2020-06-02 9 daysheat dome · 5/9 d · Z500 +258 m
peak 164k km² on 2020-05-31 · max +10.6 °C · mean +6.4 °C · burden 976k km²·d · drift 165 km (51.5 N -1.6 E → 52.9 N -2.7 E)
Event #16 — 2020-07-28 → 2020-08-02 6 daysno overlying high
peak 260k km² on 2020-07-31 · max +8.0 °C · mean +5.2 °C · burden 820k km²·d · drift 288 km (42.6 N 20.0 E → 40.0 N 20.3 E)
Event #22 — 2020-08-19 → 2020-08-28 10 dayshigh on 3/10 d only
peak 247k km² on 2020-08-26 · max +7.8 °C · mean +5.4 °C · burden 811k km²·d · drift 86 km (38.0 N -2.6 E → 38.1 N -1.7 E)
Event #18 — 2020-08-06 → 2020-08-17 12 dayshigh on 6/12 d only
peak 166k km² on 2020-08-12 · max +12.8 °C · mean +7.0 °C · burden 759k km²·d · drift 742 km (51.3 N 0.6 E → 57.1 N -5.2 E)
Event #15 — 2020-07-27 → 2020-08-02 7 dayshigh on 1/7 d only
peak 220k km² on 2020-07-31 · max +12.8 °C · mean +6.6 °C · burden 728k km²·d · drift 134 km (45.3 N 6.7 E → 44.1 N 6.7 E)
Event #1 — 2020-05-01 → 2020-05-09 9 daysheat dome · 7/9 d · Z500 +179 m
peak 173k km² on 2020-05-05 · max +16.0 °C · mean +9.0 °C · burden 717k km²·d · drift 248 km (35.2 N 4.6 E → 35.5 N 1.9 E)
Event #11 — 2020-07-04 → 2020-07-09 6 daysheat dome · 4/6 d · Z500 +144 m
peak 195k km² on 2020-07-07 · max +9.9 °C · mean +6.7 °C · burden 669k km²·d · drift 471 km (38.1 N -8.5 E → 42.0 N -6.2 E)
Event #21 — 2020-08-18 → 2020-08-22 5 daysno overlying high
peak 199k km² on 2020-08-20 · max +9.7 °C · mean +6.3 °C · burden 599k km²·d · drift 747 km (60.5 N 21.5 E → 65.4 N 31.7 E)
Event #5 — 2020-06-03 → 2020-06-10 8 dayshigh on 3/8 d only
peak 149k km² on 2020-06-08 · max +14.5 °C · mean +9.8 °C · burden 544k km²·d · drift 670 km (67.1 N 44.1 E → 61.1 N 42.9 E)
Event #20 — 2020-08-14 → 2020-08-23 10 daysno overlying high
peak 103k km² on 2020-08-19 · max +8.2 °C · mean +5.3 °C · burden 491k km²·d · drift 451 km (35.2 N 10.4 E → 35.3 N 5.5 E)
Event #8 — 2020-06-23 → 2020-06-26 4 dayshigh on 1/4 d only
peak 146k km² on 2020-06-24 · max +11.4 °C · mean +7.9 °C · burden 483k km²·d · drift 76 km (52.6 N -1.5 E → 53.2 N -1.1 E)
Event #25 — 2020-09-08 → 2020-09-13 6 dayshigh on 2/6 d only
peak 131k km² on 2020-09-12 · max +11.6 °C · mean +6.7 °C · burden 459k km²·d · drift 266 km (43.0 N -8.8 E → 41.1 N -6.8 E)
Event #9 — 2020-06-24 → 2020-06-27 4 dayshigh on 2/4 d only
peak 123k km² on 2020-06-26 · max +10.5 °C · mean +7.7 °C · burden 396k km²·d · drift 277 km (53.2 N 6.9 E → 55.1 N 9.6 E)
Event #12 — 2020-07-15 → 2020-07-22 8 dayshigh on 1/8 d only
peak 107k km² on 2020-07-18 · max +11.2 °C · mean +6.0 °C · burden 391k km²·d · drift 236 km (40.1 N -8.7 E → 42.0 N -7.5 E)
Event #14 — 2020-07-26 → 2020-07-30 5 daysno overlying high
peak 120k km² on 2020-07-28 · max +7.0 °C · mean +4.6 °C · burden 384k km²·d · drift 170 km (35.3 N 39.8 E → 35.4 N 41.7 E)
Event #26 — 2020-09-13 → 2020-09-16 4 dayshigh on 2/4 d only
peak 127k km² on 2020-09-14 · max +10.3 °C · mean +7.3 °C · burden 301k km²·d · drift 202 km (52.9 N -0.6 E → 51.2 N -1.7 E)
Filled area is the event footprint in km² (left axis); the solid line is the peak anomaly inside it and the dashed line the mean (right axis). The small panel is the centroid path, circles sized by area and the ring marking day one. Drift is the straight-line start-to-end distance, so a dome that wandered and returned reports a small number.