KS and NE Red Flag Warning Climatology

Scott Mentzer

Todd Shoemake

NWS Goodland, Kansas

Some Background info…

Red Flag program Highlights life threatening fire conditions to fire

fighters and other fire management officials Assuming dry fuels exist, program is based

primarily on surface winds and RH

Full Fire WX program became operational across NE and KS this week including a Red Flag Program

Some Background info…

• KS statewide fire management meeting held on 4/20/06 in Salina

Implemented RFW program Defined criteria for the program, West vs. East

• NE statewide fire management meeting held on 6/20/06 in Hastings

RFW climatology for NE was presented RFW program was implemented with thresholds

based on presented climatology

Purpose• Provide data to discussion about Red Flag

Warning criteria

• Provide useful information to NWS offices regarding staffing strategies

• Provide useful information to NWS forecasters about normal red flag start and stop times

Methodology • Hourly surface weather observations were obtained for

30 years (1976-2005) at the following KS sites: Goodland (GLD) Hill City (HLC) Garden City (GCK) Dodge City (DDC) Concordia (CNK) Salina (SLN) Wichita (ICT) Topeka (TOP) Chanute (CNU)

Methodology (continued)• Hourly surface weather observations were obtained for

30 years (1976-2005) at the following NE sites: Valentine (VTN) North Platte (LBF) McCook (MCK) Hastings (GID) Norfolk (OFK) Omaha (OMA)

Methodology (Continued)• Roughly 3.9 million observations were reviewed using

Excel and locally written code.

• The study examined possible wind and relative humidity thresholds for red flag warnings:– Criteria 1 (winds >=15 mph / RH <15%)– Criteria 2 (winds >=25 mph / RH <15%)– Criteria 3 (winds >=15 mph / RH <20%)– Criteria 4 (winds >= 25 mph / RH <20%)

• Fuel information is not included in the study.

Criteria 1 Criteria 2 Criteria 3 Criteria 4

Station

<15%

>15 mph

<15%

>25 mph

<20%

>15 mph

<20%

>25 mph

OMA 20 11 106 101

OFK 105 64 248 233

GID 94 53 265 209

LBF 201 111 775 374

MCK 289 160 751 433

VTN 329 91 990 423

Number of NE Events 1976-2005

Criteria 1 Criteria 2 Criteria 3 Criteria 4

Station

<15%

>15 mph

<15%

>25 mph

<20%

>15 mph

<20%

>25 mph

OMA 1 < 1 4 3

OFK 4 2 8 8

GID 3 2 9 7

LBF 7 4 26 12

MCK 10 5 25 14

VTN 11 3 33 14

Average Number of NE Events / Year

Number of KS Events 1976-2005

Station<15%

>25 mph Station<20%

>15 mph

GLD 372 CNK 177

HLC 185 SLN 221

GCK 303 ICT 237

DDC 273 TOP 132

CNU 79

Average Number of KS Events / Year

Station<15%

>25 mph Station<20%

>15 mph

GLD 12 CNK 6

HLC 6 SLN 7

GCK 10 ICT 8

DDC 9 TOP 4

CNU 3

RH <= 15%

Wind >= 25mph

STATION EVENTS PER

YEAR

GCK 10

DDC 9

DODGE CITY CWA YEARLY RED FLAG EVENTS DDC,GCK 1976-2005

0

5

10

15

20

25

30

35

YEAR

# R

ED

FL

AG

EV

EN

TS

DDC

GCK

When do these events begin?

Avg Start Time = 20:16Z (14:16 LST / 15:16 LDT)

Avg Event Length ~ 2.9 hours

DODGE CITY RED FLAG EVENTS BY START TIME1976-2005

2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

12

22

53

64 62

40

15

3

0

10

20

30

40

50

60

70

HOUR (UTC)

# R

ED

FL

AG

EV

EN

TS

LBF Start Times…

Avg Start Time = 20:33Z (14:33LST / 15:33 LDT)

Avg Event Length ~ 2.3 hours

LBF RED FLAG EVENTS BY START TIME1976-2005

0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 1

6

18

38

25

10 10

2

0

5

10

15

20

25

30

35

40

HOUR (UTC)

# R

ED

FL

AG

EV

EN

TS

OFK Start Times…

Avg Start Time = 20:14Z (14:14LST / 15:14 LDT)

Avg Event Length ~ 2.7 hours

OFK RED FLAG EVENTS BY START TIME1976-2005

0 0 0 1 0 0 0 0 1 1 0 0 0 0 2 4 6

23

40

61

4640

19

4

0

10

20

30

40

50

60

70

HOUR (UTC)

# R

ED

FL

AG

EV

EN

TS

ICT Start Times…

Avg Start Time = 20:01Z (14:01LST / 15:01 LDT)

Avg Event Length ~ 3.1 hours

WICHITA RED FLAG EVENTS BY START TIME1976-2005

1 0 0 0 0 0 0 0 0 0 0 0 0 0 0

69

23

5156

52

25

13

10

10

20

30

40

50

60

HOUR (UTC)

# R

ED

FL

AG

EV

EN

TS

Is there a “Red Flag Season” in the High Plains?

DODGE CITY RED FLAG EVENTS BY SEASON

JFM34%

AMJ36%

JAS10%

OND20%

JFM AMJ JAS OND

North Platte, NE

LBF RED FLAG EVENTS BY SEASON

JFM29%

AMJ36%

JAS13%

OND22%

JFM AMJ JAS OND

Norfolk, NE

OFK RED FLAG EVENTS BY SEASON

JFM23%

AMJ47%

JAS9%

OND21%

JFM AMJ JAS OND

Wichita, KS

WICHITA RED FLAG EVENTS BY SEASON

JFM33%

AMJ16%

JAS30%

OND21%

JFM AMJ JAS OND

Some Conclusions…

• Red Flag events throughout the KS and NE domain typically start between 2000-2100UTC.

• There is no “well-defined” Red Flag season

• The preliminary thresholds that were established for KS agree with climatology and seem sufficient for Fire WX Operations.

Previous data along with the remaining KS and NE sites are available online at:

http://www.crh.noaa.gov/gld/?n=firewx/redflagclimo.php

Data Online…

Hopefully this data will act as a planning tool for fellow NWS personnel as well as Fire Management officials.