Appendix

Table 1. Climate variables and type of statistical model used in each ecoregion in the catastrophe model domain. VPD denotes vapor pressure deficit and pr denotes precipitation.
Ecoregion	Name	Variables	Model
1	Coast Range	VPD	Dynamic
2	Puget Lowland	VPD	Static
3	Willamette Valley	VPD	Dynamic
4	Cascades	VPD	Dynamic
5	Sierra Nevada	VPD	Dynamic
6	Central California Foothills and Coastal Mountains	VPD, pr	Dynamic
7	Central California Valley	pr	Static
8	Southern California Mountains	VPD	Dynamic
9	Eastern Cascades Slopes and Foothills	VPD	Dynamic
10	Columbia Plateau	VPD	Dynamic
11	Blue Mountains	VPD	Dynamic
12	Snake River Plain	pr	Static
13	Central Basin and Range	VPD, pr	Static
14	Mojave Basin and Range	pr	Static
15	Northern Rockies	VPD	Dynamic
16	Idaho Batholith	VPD	Dynamic
17	Middle Rockies	VPD	Dynamic
18	Wyoming Basin	VPD, pr	Dynamic
19	Wasatch and Uinta Mountains	VPD	Dynamic
20	Colorado Plateaus	VPD	Dynamic
21	Southern Rockies	VPD	Dynamic
22	Arizona/New Mexico Plateau	VPD	Dynamic
23	Arizona/New Mexico Mountains	VPD	Dynamic
24	Chihuahuan Deserts	VPD, pr	Dynamic
25	High Plains	VPD	Dynamic
26	Southwestern Tablelands	pr	Static
27	Central Great Plains	VPD, pr	Static
28	Flint Hills	VPD	Static
29	Cross Timbers	VPD	Static
30	Edwards Plateau	VPD	Dynamic
31	Southern Texas Plains	pr	Static
32	Texas Blackland Prairies	VPD	Dynamic
33	East Central Texas Plains	VPD	Dynamic
34	Western Gulf Coastal Plain	VPD	Dynamic
35	South Central Plains	VPD	Dynamic
36	Ouachita Mountains	VPD	Static
37	Arkansas Valley	VPD	Static
38	Boston Mountains	VPD, pr	Static
39	Ozark Highlands	VPD, pr	Static
40	Central Irregular Plains	VPD	Static
41	Canadian Rockies	VPD	Dynamic
42	Northwestern Glaciated Plains	VPD	Static
43	Northwestern Great Plains	VPD, pr	Dynamic
77	North Cascades	VPD	Dynamic
78	Klamath Mountains/California High North Coast Range	VPD	Dynamic
79	Madrean Archipelago	VPD	Dynamic
80	Northern Basin and Range	VPD, pr	Dynamic
81	Sonoran Basin and Range	pr	Static
85	Southern California/Northern Baja Coast	VPD	Static

Figure 1. Environmental Protection Agency level III ecoregions of the continental United States. Domain of the model is denoted by the thick gray line.

Table 2. Climate models that were assessed and the six models selected to create future climate projections
Historical Assessment	Future Projections
ACCESS-CM2	ACCESS-ESM1-5
ACCESS-ESM1-5	CanESM5
CanESM5	FGOALS-g3
CMCC-ESM2	GISS-E2-1-G
CNRM-CM6-1	INM-CM4-8
CNRM-ESM2-1	NorESM2-LM
EC-Earth3
EC-Earth3-Veg-LR
FGOALS-g3
GFDL-ESM4
GISS-E2-1-G
INM-CM4-8
INM-CM5-0
IPSL-CM6A-LR
KACE-1-0-G
MIROC-ES2L
MIROC6
MPI-ESM1-2-HR
MPI-ESM1-2-LR
MRI-ESM2-0
NorESM2-LM
NorESM2-MM
TaiESM1
UKESM1-0-LL

Table 3. Percent (%) change in May-to-October mean vapor pressure deficit (VPD) based on the mean of six GCMs for each ecoregion by scenario and time-horizon.
	SSP1-2.6				SSP2-4.5			SSP3-7.0		SSP5-8.5
Eco- region	2030	2050	2075	2100	2030	2050	2075	2030	2050	2030	2050
1	5	9	10	11	4	8	12	5	13	4	10
2	5	8	9	11	5	11	17	5	16	6	15
3	4	8	9	10	4	9	14	5	13	4	12
4	4	7	8	9	4	9	14	5	12	5	13
5	3	5	6	5	3	7	11	3	9	4	10
6	4	7	8	7	3	6	9	4	9	3	9
7	3	6	7	6	3	7	9	3	9	3	9
8	3	6	7	6	3	7	10	4	10	3	9
9	4	6	8	9	4	9	14	4	12	4	12
10	5	8	9	11	5	12	18	6	16	6	16
11	4	7	8	9	5	11	16	5	14	5	14
12	4	7	8	8	5	11	15	5	13	5	14
13	3	6	7	6	4	9	13	4	11	4	12
14	3	5	6	5	3	8	11	3	10	4	11
15	4	8	9	10	6	12	17	6	16	6	16
16	4	7	8	9	5	11	16	5	14	5	15
17	4	7	8	7	4	10	14	5	12	5	15
18	3	7	7	5	4	9	13	4	11	5	14
19	3	7	7	6	4	10	14	4	12	5	14
20	3	6	7	5	4	9	13	4	11	5	14
21	3	7	7	4	4	9	14	4	11	5	15
22	3	6	6	4	3	8	13	4	11	4	13
23	3	6	6	4	3	8	12	3	10	4	13
24	3	6	6	2	3	8	12	3	11	5	14
25	4	8	8	5	4	10	14	4	12	6	16
26	3	7	7	4	4	10	14	4	11	5	15
27	4	8	9	6	5	12	16	5	13	6	17
28	4	9	9	6	5	14	18	5	14	6	19
29	4	7	7	4	5	12	14	4	11	5	15
30	3	6	6	3	4	9	11	3	10	5	14
31	3	6	7	3	3	8	10	3	10	5	13
32	3	6	7	4	4	11	13	4	11	5	14
33	3	6	7	4	4	10	12	4	10	5	14
34	3	6	7	5	3	7	9	4	10	3	10
35	3	6	6	4	4	12	14	4	11	5	15
36	4	7	7	3	5	14	17	4	12	6	17
37	4	7	7	3	5	14	18	4	13	6	18
38	4	8	8	3	6	15	19	5	14	6	19
39	5	10	10	6	6	16	21	6	16	7	21
40	5	10	10	7	6	16	21	6	16	7	21
41	4	7	8	9	5	11	15	5	14	5	14
42	4	8	9	10	5	11	15	5	14	6	17
43	4	8	9	8	5	10	14	5	13	6	16
77	5	9	10	12	6	13	20	6	18	7	18
78	4	7	8	9	3	7	11	4	11	4	10
79	3	6	6	4	3	8	12	3	10	4	12
80	4	7	8	8	4	10	15	5	12	5	13
81	3	5	6	4	3	7	11	3	9	4	11
85	4	7	8	7	3	6	9	4	10	3	9

Table 4. Percent (%) change in annual total precipitation based on the mean of six GCMs for each ecoregion by scenario and time-horizon.
	SSP1-2.6				SSP2-4.5			SSP3-7.0		SSP5-8.5
Eco- region	2030	2050	2075	2100	2030	2050	2075	2030	2050	2030	2050
1	1	4	5	3	1	3	3	1	2	2	4
2	2	5	7	5	2	4	6	1	3	2	5
3	2	4	5	3	1	4	4	1	3	2	4
4	2	4	5	3	1	4	4	1	3	2	5
5	1	2	2	-1	0	-1	-3	0	0	2	5
6	1	2	1	-3	0	-1	-4	-1	-2	1	3
7	1	2	1	-2	0	-1	-4	-1	-2	1	3
8	1	3	1	-2	-1	-2	-4	-1	-2	1	0
9	2	4	5	3	1	4	4	1	4	3	7
10	2	5	6	4	2	5	6	1	4	2	6
11	2	5	5	3	2	5	6	1	5	3	7
12	2	4	5	3	2	4	6	1	6	3	8
13	1	3	4	4	1	2	2	1	3	2	7
14	1	3	2	1	0	0	-2	0	1	1	2
15	2	5	6	5	2	6	8	1	5	2	7
16	2	5	5	2	2	5	6	1	5	3	7
17	2	5	6	4	2	5	9	2	6	3	8
18	2	4	5	5	2	6	9	2	6	2	7
19	1	2	3	5	1	3	3	1	3	2	5
20	1	2	2	5	2	3	3	1	3	1	4
21	2	3	2	4	2	4	5	2	4	1	3
22	1	1	2	6	2	3	2	1	1	0	0
23	1	1	2	6	1	3	2	1	1	0	-1
24	1	2	3	6	0	2	4	1	1	-1	-2
25	1	2	2	3	1	2	4	1	2	0	1
26	1	2	1	1	1	1	2	0	1	0	-1
27	1	2	2	2	0	1	2	0	2	0	1
28	1	2	2	3	1	1	2	1	2	1	1
29	0	1	1	2	-1	-2	0	0	0	0	-1
30	0	1	1	5	0	-1	3	0	0	-1	-2
31	1	2	2	5	0	0	4	0	1	-1	-2
32	0	0	0	3	-1	-2	0	-1	-1	0	-2
33	0	0	0	4	0	-2	0	0	-1	0	-2
34	0	1	1	4	0	-1	1	0	-1	-1	-2
35	0	0	1	5	0	-1	1	0	0	0	0
36	0	1	2	5	0	-1	0	0	0	1	1
37	0	1	2	5	0	-1	0	0	0	1	1
38	1	1	2	4	0	-1	0	0	1	1	1
39	1	2	2	3	0	0	1	1	1	1	2
40	1	2	2	2	1	1	2	1	2	1	3
41	2	5	7	7	2	5	9	2	6	3	9
42	2	4	5	3	1	4	7	1	4	2	6
43	2	3	4	3	1	4	8	1	4	2	6
77	2	6	7	5	2	5	6	1	3	2	5
78	1	2	2	0	1	2	0	1	1	2	4
79	1	0	1	7	2	5	1	1	0	0	-3
80	2	4	5	3	2	4	5	2	6	3	8
81	1	1	3	8	1	3	0	1	1	0	-2
85	1	3	1	-2	-1	-2	-3	-1	-2	0	-1

Table 5. Percent (%) change in average annual burn area based on the mean of six GCMs for each ecoregion by scenario and time-horizon.
	SSP1-2.6		SSP2-4.5		SSP3-7.0		SSP5-8.5
Ecoregion	2030	2050	2030	2050	2030	2050	2030	2050
1	124	331	86	316	145	1030	96	726
2	5	9	6	12	6	18	6	17
3	18	36	17	42	21	69	19	65
4	85	185	100	308	115	489	112	531
5	23	42	25	63	28	86	29	99
6	29	57	22	51	30	83	26	88
7	0	1	0	-1	0	-1	1	2
8	36	62	31	76	45	110	38	111
9	28	56	35	93	37	132	38	139
10	5	8	6	12	6	18	6	18
11	39	78	51	143	55	215	55	225
12	5	12	4	13	4	16	8	23
13	20	47	24	67	26	95	34	132
14	3	7	1	0	1	3	3	6
15	44	100	61	166	64	276	64	280
16	52	102	70	189	77	259	78	294
17	46	112	61	188	63	270	71	364
18	33	78	41	122	42	167	52	234
19	28	61	33	100	36	145	44	184
20	39	95	47	162	51	255	67	366
21	49	129	59	224	63	356	91	584
22	5	11	6	16	6	21	8	26
23	15	32	18	47	19	66	24	85
24	43	107	47	166	51	250	62	335
25	16	35	18	49	18	62	25	88
26	3	8	2	5	2	3	0	-2
27	22	51	18	49	18	63	22	74
28	4	8	5	12	4	13	6	17
29	5	10	7	18	6	17	7	23
30	22	51	24	73	21	91	34	137
31	2	7	0	1	1	3	-2	-4
32	16	37	20	64	17	62	24	90
33	11	23	13	38	12	40	15	55
34	9	17	7	19	9	27	9	30
35	11	23	15	46	13	43	17	61
36	1	2	1	3	1	3	1	4
37	1	2	1	4	1	3	1	4
38	2	4	2	5	2	6	3	8
39	3	6	3	8	3	9	4	13
40	1	1	1	2	1	2	1	3
41	65	158	93	272	94	445	93	484
42	11	25	14	33	15	46	17	57
43	35	89	41	120	43	170	54	245
77	59	128	78	216	86	359	92	378
78	67	111	59	126	81	186	62	191
79	19	42	22	60	23	86	30	113
80	28	56	35	93	37	128	41	148
81	2	4	3	8	3	4	1	-3
85	9	18	6	17	10	28	7	23

Table 6. Percent (%) change in average annual loss (AAL), annual occurrence loss (AOL) and aggregate and occurrence loss exceeded for return periods 2- to 1000-year to the Verisk industry exposure database for each scenario and time-horizon based on the U.S. Wildfire 10,000-year catalog.
Scenario	Horizon	Agg/Occ	AAL	2-yr	5-yr	10-yr	20-yr	50-yr	100-yr	200-yr	500-yr	1000-yr
SSP1-2.6	2030	Agg	22	30	21	18	15	13	9	9	3	6
SSP1-2.6	2050	Agg	46	66	47	36	30	20	20	15	14	22
SSP1-2.6	2030	Occ	19	26	19	17	17	18	13	15	9	4
SSP1-2.6	2050	Occ	37	50	42	33	32	28	18	17	9	5
SSP2-4.5	2030	Agg	21	30	21	15	12	11	8	6	3	2
SSP2-4.5	2050	Agg	58	80	56	46	35	27	27	22	21	38
SSP2-4.5	2030	Occ	16	25	18	15	13	9	7	7	4	0
SSP2-4.5	2050	Occ	42	57	43	34	33	32	22	20	11	11
SSP3-7.0	2030	Agg	26	36	25	21	16	14	10	10	7	6
SSP3-7.0	2050	Agg	97	136	95	76	61	45	35	30	20	26
SSP3-7.0	2030	Occ	20	30	22	18	16	10	12	13	9	4
SSP3-7.0	2050	Occ	76	98	82	75	65	55	35	23	9	4
SSP5-8.5	2030	Agg	25	36	25	20	16	12	8	9	10	16
SSP5-8.5	2050	Agg	104	151	99	76	60	44	41	30	25	36
SSP5-8.5	2030	Occ	19	27	21	18	14	10	10	12	9	5
SSP5-8.5	2050	Occ	73	105	78	66	59	48	32	20	9	11

Table 7. Percent (%) change in average annual loss (AAL) by U.S. state from the Verisk industry exposure database for each scenario and time-horizon based on the U.S. Wildfire 10,000-year catalog.
Scenario	Horizon	AZ	CA	CO	ID	MT	NM	NV	OK	OR	TX	UT	WA	WY
SSP1-2.6	2030	7	23	33	23	42	26	17	5	41	14	22	24	31
SSP1-2.6	2050	16	46	82	54	109	65	44	11	96	33	47	49	88
SSP2-4.5	2030	10	19	40	26	59	29	22	5	49	13	26	29	42
SSP2-4.5	2050	25	50	145	80	181	93	64	14	134	47	73	78	133
SSP3-7.0	2030	11	26	41	36	58	29	24	5	60	15	27	31	43
SSP3-7.0	2050	33	90	226	112	261	162	89	16	229	58	113	142	182
SSP5-8.5	2030	11	22	64	34	67	43	27	7	52	21	37	30	53
SSP5-8.5	2050	34	84	360	127	331	257	113	22	227	83	154	139	272

Table 8. Top three counties in each state that contribute to the present-day industry average annual loss (AAL).
State	Rank	County
Arizona	1	Maricopa
Arizona	2	Pima
Arizona	3	Pinal
California	1	San Bernardino
California	2	Riverside
California	3	Los Angeles
Colorado	1	El Paso
Colorado	2	Boulder
Colorado	3	Douglas
Idaho	1	Ada
Idaho	2	Elmore
Idaho	3	Blaine
Montana	1	Missoula
Montana	2	Yellowstone
Montana	3	Flathead
Nevada	1	Washoe
Nevada	2	Elko
Nevada	3	Douglas
New Mexico	1	Lincoln
New Mexico	2	Santa Fe
New Mexico	3	Bernalillo
Oklahoma	1	Tulsa
Oklahoma	2	Osage
Oklahoma	3	Pittsburg
Oregon	1	Deschutes
Oregon	2	Jackson
Oregon	3	Josephine
Texas	1	Travis
Texas	2	Bexar
Texas	3	Hays
Utah	1	Utah
Utah	2	Washington
Utah	3	Salt Lake
Washington	1	Yakima
Washington	2	Benton
Washington	3	Chelan
Wyoming	1	Natrona
Wyoming	2	Teton
Wyoming	3	Fremont