Every heat event the pipeline tracked between 2009-05-01 and 2009-09-30, with how each one grew, peaked and moved. Anomalies are against the 1991–2020 baseline.
Season at a glance
Events tracked
19
Total heat burden
31.24 Mkm²·days
Longest
16days (#2)
Hottest
+13.6°C (#4)
With a heat dome
10of 19 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 #12 — 2009-06-23 → 2009-07-05 13 daysheat dome · 11/13 d · Z500 +258 m
peak 792k km² on 2009-06-27 · max +13.1 °C · mean +7.8 °C · burden 4.95 M km²·d · drift 253 km (60.6 N 12.4 E → 60.5 N 7.8 E)
Event #2 — 2009-05-14 → 2009-05-29 16 daysheat dome · 10/16 d · Z500 +149 m
peak 815k km² on 2009-05-24 · max +12.1 °C · mean +7.0 °C · burden 4.77 M km²·d · drift 1100 km (43.3 N 22.4 E → 44.5 N 8.8 E)
Event #14 — 2009-07-10 → 2009-07-20 11 dayshigh on 3/11 d only
peak 650k km² on 2009-07-17 · max +10.0 °C · mean +6.7 °C · burden 3.42 M km²·d · drift 422 km (50.2 N 44.9 E → 47.4 N 40.9 E)
Event #18 — 2009-09-02 → 2009-09-10 9 daysheat dome · 6/9 d · Z500 +235 m
peak 592k km² on 2009-09-05 · max +11.0 °C · mean +8.0 °C · burden 2.88 M km²·d · drift 1225 km (62.9 N 36.5 E → 51.9 N 38.3 E)
Event #10 — 2009-06-20 → 2009-06-30 11 dayshigh on 1/11 d only
peak 662k km² on 2009-06-24 · max +11.7 °C · mean +6.9 °C · burden 2.47 M km²·d · drift 1139 km (40.1 N 31.0 E → 50.4 N 31.2 E)
Event #8 — 2009-06-09 → 2009-06-15 7 daysheat dome · 6/7 d · Z500 +229 m
peak 652k km² on 2009-06-12 · max +12.7 °C · mean +7.7 °C · burden 2.27 M km²·d · drift 1160 km (50.0 N 37.0 E → 59.7 N 43.9 E)
Event #17 — 2009-08-13 → 2009-08-24 12 dayshigh on 5/12 d only
peak 358k km² on 2009-08-19 · max +11.4 °C · mean +5.5 °C · burden 1.73 M km²·d · drift 592 km (43.2 N 3.3 E → 43.4 N 10.6 E)
Event #7 — 2009-06-06 → 2009-06-12 7 daysheat dome · 6/7 d · Z500 +169 m
peak 426k km² on 2009-06-10 · max +9.7 °C · mean +6.6 °C · burden 1.40 M km²·d · drift 1014 km (42.1 N 26.3 E → 50.4 N 31.9 E)
Event #16 — 2009-07-31 → 2009-08-10 11 dayshigh on 4/11 d only
peak 247k km² on 2009-08-08 · max +10.9 °C · mean +6.9 °C · burden 1.04 M km²·d · drift 633 km (69.6 N 19.2 E → 64.5 N 26.0 E)
Event #15 — 2009-07-21 → 2009-07-29 9 dayshigh on 2/9 d only
peak 175k km² on 2009-07-24 · max +11.0 °C · mean +5.2 °C · burden 775k km²·d · drift 151 km (35.9 N 1.6 E → 35.5 N 3.2 E)
Event #3 — 2009-05-15 → 2009-05-21 7 daysheat dome · 5/7 d · Z500 +124 m
peak 234k km² on 2009-05-19 · max +8.5 °C · mean +5.9 °C · burden 757k km²·d · drift 280 km (40.3 N 43.5 E → 38.4 N 41.3 E)
Event #9 — 2009-06-10 → 2009-06-16 7 daysheat dome · 5/7 d · Z500 +132 m
peak 213k km² on 2009-06-13 · max +10.4 °C · mean +7.0 °C · burden 755k km²·d · drift 633 km (40.2 N -0.6 E → 36.3 N -5.8 E)
Event #19 — 2009-09-20 → 2009-09-24 5 dayshigh on 2/5 d only
peak 214k km² on 2009-09-22 · max +8.5 °C · mean +6.5 °C · burden 725k km²·d · drift 304 km (50.0 N 17.5 E → 47.7 N 19.5 E)
Event #11 — 2009-06-23 → 2009-07-05 13 dayshigh on 6/13 d only
peak 142k km² on 2009-07-02 · max +9.6 °C · mean +6.4 °C · burden 672k km²·d · drift 68 km (57.7 N -4.8 E → 58.2 N -4.2 E)
Event #5 — 2009-05-27 → 2009-06-02 7 daysno overlying high
peak 171k km² on 2009-05-30 · max +11.5 °C · mean +7.6 °C · burden 659k km²·d · drift 308 km (38.1 N -8.7 E → 40.6 N -7.2 E)
Event #4 — 2009-05-18 → 2009-05-26 9 daysheat dome · 5/9 d · Z500 +149 m
peak 143k km² on 2009-05-22 · max +13.6 °C · mean +7.6 °C · burden 566k km²·d · drift 650 km (35.0 N 3.5 E → 36.2 N 10.5 E)
Event #1 — 2009-05-02 → 2009-05-08 7 daysheat dome · 4/7 d · Z500 +206 m
peak 127k km² on 2009-05-05 · max +10.2 °C · mean +7.3 °C · burden 505k km²·d · drift 421 km (39.4 N -8.9 E → 42.4 N -5.8 E)
Event #6 — 2009-05-28 → 2009-06-03 7 daysheat dome · 5/7 d · Z500 +273 m
peak 144k km² on 2009-06-01 · max +9.8 °C · mean +6.4 °C · burden 490k km²·d · drift 691 km (57.1 N -2.9 E → 50.9 N -3.7 E)
Event #13 — 2009-06-28 → 2009-07-02 5 daysno overlying high
peak 120k km² on 2009-06-30 · max +9.8 °C · mean +7.1 °C · burden 425k km²·d · drift 340 km (45.8 N -0.6 E → 48.7 N 0.7 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.