Bear Lodge Mountains Tornado
July 13 2009

A Special Case Study

Jonathan D. Finch

Under Construction!!


Related items of interest


Historical Tornado Cases for the Cheyenne Warning Area

Detailed Tornado Cases for the Cheyenne Warning Area      

Historical Tornado Cases for the Boulder Warning Area

Historical Tornado Cases for the United States

Elevated Mixed Layer

Elevated Heating

High plains and front range topo maps



Overview with Radar Imagery

Several storms developed around 20 UTC (2 pm MDT) over the Big Horn Mountains. The northenmost storm developed around 2000 UTC in Montana to the north of Sheep Mountain (located in Wyoming) and was the most severe initially. This storm produced 1.5" hail 22 miles southwest of Lodge Grass MT. Another storm developed as a shower passed over the crest of the Bighorns. Another storm developed about 15 miles south-southeast of Burgess Junction at 2015 UTC. The southern two storms eventually merged into one storm east of Sheridan and became the dominant storm after the northern storm weakened, producing severe weather from 2045 UTC (245 pm MDT) through 0045 UTC (645 pm MDT). The Sheridan and Rapid City radars were the closest and show the storm progressing across northern Wyoming.

The storm encountered an outflow boundary west of Hulett, WY before 00 UTC (6 pm MDT). Winds were easterly on the cool side of the boundary with lower temperatures and higher dewpoints. Hence the storm suddenly moved into an area with high surface based CAPE, low LCL heights, and high vertical wind shear. Unfortunately there is no radar close to the affected region. I used the mesowest site to create radar mosaics with radar overlaid. The first loop is regional while the 2nd loop is more zoomed in to the affected region. In these loops you can clearly see that the storm that pounded the Bear Lodge Mountain region developed from 2 individual storms that combined after initiating over the Bighorn Mountains.


Here are 3 radar loops from the Rapid City radar. One loop starts at 1540Z and the other 2 loops start at approximately 1730 and 1945 UTC.

Hail Documentation

I gathered severe weather reports from a variety of sources to thoroughly document this storm including the National Weather Service. I called residents in the affected areas to get additional documentation including pictures.

The storm moved across sparsely populated areas north of Recluse and north of Weston. 1" hail was reported 9 miles east-northeast of Sheridan at 2115 UTC (315 MDT). Golfball sized hail occurred at 2215 UTC (415 MDT) 15 miles north-northwest of Recluse near the Montana border. At 2300 UTC, 1.25" hail was reported 13 miles northeast of Weston.

After the storm crossed the surface boundary there were numerous reports of baseball to softball or larger hail with considerable damage. Golfball to softball sized hail occurred in the New Haven area around 2320 UTC (520 pm MDT).

South-southwest of Hulett about 3 or 4 miles, hailstones broke through the ceiling (composed of tin sheet, insulation and plywood) of the mobile home belonging to Sue Saunders and into the living area. Here is another picture of the torn tin.

B. Pemberton of Hulett photographed this hailstone. He kept it in his freezer for 2 weeks. Then he found out I was looking for hail pictures. He took the hailstone out of his freezer and placed it next to a tape measure. I  believe he lives in the Whitetail Creek Rd. area. This is in the same general area as Susan Sanders.

I obtained a picture from the Sundance Times that shows several large hailstones. They also provided me with damage pictures.

Cassandra Penning took several pictures of the hail and hail damage. The hail severely damaged a car.

The Nelsen's (neighbors of Sue Saunders) on Blacktail Creek Rd. also received a lot of damage.
Elizabeth Nelsen reported orange size hail. The hail broke through 2 layers of shingles and 1/4" plywood covering the trailer house. I hail stone broke throug the ceiling of their trailer. Hail also broke through a plastic table in 2 places. The width of the circular hole in this table was measured at 4.5". The top of a garbage container was busted by hail. Hail smashed out windows at the Nelson Residence and broke through 2X6 redwood on their deck.

Hulett resident Jason Perry said that much of the hail near his location was baseball size, but there quite a few softball size stones. He said that a few of the hailstones were "enormous" and measured 5" in diameter at the very least.

Hulett emergency manager Sam Waugh also reported hail the size of "large grapefruits", althouth most of the hail at this place was 3" in diameter or less. Mrs. Kelly Waugh took a pictures the hail. Here are the hailstones they collected after some melting had occurred.

Mrs. Neiman who lives 1 mile south of Hulett recalls hail as large as softballs.

Kerry H. took this picture of large hail in Hulett.

Here is a large piece of hail photographed by E. J. Collins.

Mrs. Reid who lives about 9 miles west-northwest of Hulett on New Haven Rd reported baseball sized hail.

Max Morlock who lives on Ewing Rd about 7 miles west of Hulett measured 5" diameter hail. The roof of his house needed to be redone as his residence suffered extensive damage.

Several calves were killed in the hailstorm according to Iona Hauber of New Haven.

David Wolfskill who lives 8 miles west-southwest of Hulett reported tennis to softball sized hail that damaged his roof and some cars. He said that the worst of the hail damage was north of him.

Mrs. Willey who lives 4 miles southeast of Hulett on Blacktail Creek Rd was on the edge of the storm and received baseball sized hailstones spaced about 10 ft apart. One or more of the stones broke through the tin roof of their trailer. No large hail occured further southeast on Blacktail Creek Rd. 

Mrs. Mahoney who lives 7 miles nortwest of Cook Lake on Lame Jones Rd. reported baseball size hail. But they arrived some time after the storm passed and some melting may have occurred.

James Hamill who lives immediately east of Highway 24 on Blacktail Creek Rd. reported softball sized hail that broke through the metal ceiling of a trailer house.

Gary Luther who lives 4 miles west and 1/2 mile north of Cook Lake near Lame Jones Rd. measured 3.5" hail with considerable hail damage. A few oak trees on his property were uprooted. About 1 mile east of his house there were about 10 large pine trees that were either snapped off or uprooted. This marks the beginning of the tornado path. So the tornado path indicated by the Forest Service could possibly be shifted about 2 miles further west-northwest.

The Cook Lake campground host said that softball sized hail caused water to splash 40 ft in the air upon impact. This was probably an exaggeration but I will contact the host to see if he took any pictures of the hail.


Tornado Documentation

Officially, a tornado touched down immediately south of Bear Lodge (elevation 5200 ft) or just west of Cook Lake around 610 pm and moved to the east-southeast for over 9 miles, lifting a few hundred feet west of Highway 111. The following pictures were taken by Kurt Moberg of the Sundance Times. Several thousand acres of trees were downed or snapped off and some houses and barns were heavily damaged. The damage path was up to 1/2 mile wide. Many trees, some 30" in diameter, were snapped off about 10-20 ft above the ground and flung long distances. The tops of the trees in the middle of the damage path could not be found and the bottoms were debarked in some cases. 
Here is some metal object wrapped around a telephone pole. Very few structures were in the path of the tornado and the only structures hit were near the end of the damage path. The tornado was officially rated EF2 but could have been stronger in places. Phil Mason took a few pictures of the tornado as it passed 1/4 to 1/2 mile so his southwest and south. Tim Skaggs took a few pictures of the tornado near the end of its life cycle. Doris Brown who lives in Buelah took some pictures of the tornado as well. Here is her picture of the stormRichard White took a picture of the tree damage. I plotted the path in google maps.

The National Forest Service conducted a flyover of the tornado path and took quite a few pictures. Beth Steinhauer and Susanna Marking took these pictures and their names are at the bottom of the pictures. The damage path constructed from the flyover using GPS is here.

As discussed in the hail section, a few oak trees were uprooted near Lame Jones Rd or about 4 miles west and slightly north of Cook Lake. In addition, Mr. Luther who lives in the area found 10 large pine trees that were either uprooted or snapped off about 3 miles west-northwest of Cook Lake (near Lame Jones Creek). Thus the tornado may have started off around 606 pm and further west than depicted on the Forest Service map. 


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Crook County Homeland Security Coordinator Jim Pridgeon shared a few pictures with me. He told me to credit Crook County since the pictures came from a variety of sources.

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The Gillette Record took a few pictures of the structural damage to a trailer house near Farrall, WY. This damage was done at the end of the tornado path when the storm was weakening.  Here is the text of their story.


Meteorological Discussion


           
12 UTC July 13

                                        

ignore this information below. I will add appropriate numbers in this table soon,

                   


21 UTC Elev(ft) Alt. Pres.(mb) SLP(mb) T(F) Td(F) MR(g/kg) theta(F) theta-e(K)
Douglas 4900 24.95 844 1005.1 79 58 12.4 105.7
352.7
Wichita 1333 28.52 965.7 1012.6 95 61 12 100.6 348.4
Topeka 881
29.03 983 1014.9 88 70 16.3 90.7 354.7
OKC 1295 28.61 968.7 1014.2 88 67 14.8 92.7 351.8


                                      
                       
           
00 UTC July 14