Table 4. Pearson correlation coefficients (r) evaluating 16 parameters with subsets of wildfire burned area per day in southern California, USA, from 2001 to 2009.

All values listed are significant at P < 0.05; ns = not significant (P ≥ 0.05). The daily burned area dataset comprises 158 distinct wildfire events that were detected by the MODIS MCD64A1 product (Giglio et al. 2009) and Monitoring Trends in Burn Severity datasets (Eidenshink et al. 2007) and exceeded 1 km².

Parameter	All	Single-day fire events	Multi-day fire events				Burned area size		Santa AnaB
			All multi-day	First day	Middle day	Last day	<500 ha	>500 ha	non-SA	SA
n	528	67	461	89	283	89	240	288	428	100
RH	−0.47**	−0.36	−0.48**	−0.46**	−0.56**	−0.24	−0.31**	−0.31**	−0.43**	−0.26*
RH (daily minimum)	−0.43**	−0.25	−0.45**	−0.42**	−0.51**	−0.27	−0.32**	−0.23**	−0.41**	ns
RH (at 1600 hours PST)	−0.43**	−0.32*	−0.44**	−0.44**	−0.49**	−0.30*	−0.33**	−0.22**	−0.38**	−0.25
WS	ns	ns	ns	0.28	ns	ns	ns	ns	ns	ns
WS (gust)	0.17**	0.26	0.18**	0.42**	ns	ns	ns	0.18*	ns	0.21
WS (peak)	0.25**	0.37	0.25**	0.61**	0.17	ns	ns	0.17	ns	ns
FT	0.18**	ns	0.20**	ns	0.28**	ns	0.40**	ns	0.27**	ns
AT	0.18**	ns	0.20**	ns	0.31**	ns	0.40**	ns	0.29**	ns
FM	−0.36**	ns	−0.38**	−0.29	−0.46**	ns	−0.39**	ns	−0.42**	ns
SA1 h (#)	0.27**	0.36*	0.27**	0.48**	0.24**	ns	ns	0.22**	ns	0.20
PD	ns	ns	ns	0.32**	ns	0.35**	ns	ns	ns	0.30*
HD	ns	ns	ns	0.35**	ns	0.40**	ns	ns	ns	0.28*
LP	0.18**	ns	0.23**	ns	0.65**	0.44**	ns	0.16*	0.29**	ns
SL	0.16**	ns	0.18**	0.21	0.18**	ns	ns	ns	0.21**	ns
FL	0.24	ns	0.26**	ns	0.31**	0.21	0.15	0.13	0.29**	ns
FFWI	0.17**	0.28	0.17**	0.34**	ns	0.21	ns	0.12	ns	ns

^BSA refers to daily burned areas meeting any of the three definitions detailed in Table 1.

^*P ≤ 0.01;

^**P ≤ 0.001.

See Table 2 for variable names, descriptions and sources