An assessment of climate, weather, and fuel factors influencing a large, destructive wildfire in the Knysna region, South Africa

Fire Ecology

Table 2 Weather conditions at 1400 hours on the days of the 2017 Knysna Fires, and the percentage of days that these (or more extreme) conditions occurred in the long-term record at George (since 1943) and Knysna (since 1997)

2017 date	Weather variables, fire danger, and drought indices							Percentage of days that these (or worse) conditions occurred in the historic record
2017 date	Rainfall (mm)	Temp. (°C)	Humidity (%)	Wind (m s⁻¹)	FDI	DF	KBDI	Temp.	Humidity	Wind	FDI	DF	KBDI
George
06 Jun	0.0	31.2	14	7.5	38.3	9.3	91.4	0.90	0.86	8.85	0.10	0.45	0.96
07 Jun	0.0	18.6	30	13.8	24.5	9.3	91.8	56.08	5.78	0.19	0.84	0.45	0.96
08 Jun	0.0	10.5	68	8.4	3.2	9.3	91.9	98.83	61.42	6.55	20.98	0.45	0.96
09 Jun	0.0	15.9	41	3.9	6.7	9.3	92.2	81.62	13.17	49.25	9.35	0.45	0.78
10 Jun	0.1	22.4	31	11.1	21.5	9.3	92.8	21.82	6.75	1.02	1.26	0.45	0.78
11 Jun	0.0	18.4	48	4.8	6.2	9.3	93.2	56.08	21.60	34.00	9.35	0.45	0.78
Knysna
06 Jun	0.0	34.1	11	2.1	32.0	10.0	149.7	0.76	0.08	59.08	0.05	0.91	0.53
07 Jun	0.0	18.8	35	10.5	16.9	10.0	150.0	70.63	6.05	0.08	0.94	0.91	0.49
08 Jun	3.4	11.4	67	5.7	2.6	8.9	150.0	99.43	66.46	5.15	38.60	8.19	0.49
09 Jun	0.0	20.4	22	1.8	12.6	9.4	150.3	55.20	1.67	75.77	2.06	4.65	0.46
10 Jun	0.0	23.3	29	4.5	14.6	10.0	150.7	32.68	3.70	11.35	1.39	0.91	0.45
11 Jun	0.0	20.3	46	1.4	5.7	10.0	151.0	57.96	15.35	90.13	9.18	0.91	0.44

Percentages ≤ 0.2 are in boldface to indicate extreme conditions. Temp. = temperature; FDI = McArthur Forest Fire Danger Index; DF = drought factor; and KBDI = Keetch Byram Drought Index (Keetch and Byram 1968; Noble et al. 1980)