Rising peak
USBC bowler profile
Gillianne P Ostermiller
Proven Competitor
15-152700
Bowling since 2016
160+ peak
1K games
Lifetime average
143.48
Lifetime games
1121
Highest average
177
Career honors
0
What this profile flair means
Rising peak aura
The nameplate aura reflects a highest recorded league average of 177.
Proven Competitor
Awarded for at least 1,000 recorded league games.
Honor pins
Pins appear after a recognized 300 game, 800 or 900 series, or 11-in-a-row award.
Milestone marks
These celebrate peak average, career average, recorded games, and accumulated honors separately.
Historical records
League History
USBC records begin in 2016. Sport and challenge conversions are summarized below.
Recent composite averages
Year2026
Type
House
Average174
Games111
Year2026
Type
Challenge
Average150
Games150
Year2025
Type
House
Average174
Games117
League averages
2026-2027
League
MT Big Sky Tour String U15/U20 Girls
Challenge
SeasonW
Average & games
League
MT Big Sky Tour U15/U20 Girls
Challenge
SeasonW
Average & games
League
Razzle Dazzle
SeasonW
Average & games
League
Jr. Gold/Challenge League
Challenge
SeasonW
Average & games
2025-2026
League
Balls O' Fire
SeasonW
Average177
Games54
League
Razzle Dazzle
SeasonW
Average171
Games57
League
MT Big Sky Tour String U15/U20 Girls
Challenge
SeasonW
Average162
Games7
League
Jr. Gold Majors
Challenge
SeasonW
Average151
Games88
League
MT Big Sky Tour U15/U20 Girls
Challenge
SeasonW
Average148
Games55
2024-2025
League
MT Big Sky U15/U20 Girls - String
Challenge
SeasonW
Average & games
League
MT Big Sky Tour U15/U20 Girls
Challenge
SeasonW
Average & games
League
Balls O' Fire Youth
SeasonW
Average175
Games54
League
Razzle Dazzle Youth
SeasonW
Average174
Games63
League
MT Big Sky Tour U15/U20 Girls - String
Challenge
SeasonW
Average162
Games7
League
MT Big Sky Tour U15/U20 Girls
Challenge
SeasonW
Average151
Games37
League
Jr. Gold Majors
Challenge
SeasonW
Average145
Games68
Show earlier league averages Hide earlier league averages
2023-2024
League
MT Big Sky Tour - Major U20
Challenge
SeasonW
Average & games
League
Razzle Dazzle
SeasonW
Average164
Games42
League
Balls O' Fire
SeasonW
Average162
Games63
League
MT Big Sky Tour - Major U20
Challenge
SeasonW
Average149
Games53
League
Jr. Gold Majors
Challenge
SeasonW
Average146
Games91
2022-2023
League
MT Big Sky Tour - Major U20
Challenge
SeasonW
Average & games
League
Balls O' Fire
SeasonW
Average137
Games41
League
Jr Gold Majors
Challenge
SeasonW
Average133
Games28
League
MT Big Sky Tour - Junior (U15)
Challenge
SeasonW
Average131
Games46
2021-2022
League
Balls O Fire
SeasonW
Average133
Games36
League
MT Big Sky Tour - Junior (U15)
Challenge
SeasonW
Average120
Games18
2020-2021
League
Ball O Fire
SeasonW
Average127
Games63
2019-2020
League
Spitfires
SeasonW
Average120
Games30
2018-2019
League
Spitfires
SeasonW
Average106
Games32
2017-2018
League
Spitfires
SeasonW
Average103
Games26
2016-2017
League
Spitfires
SeasonW
Average79
Games28
2015-2016
League
Spitfires
SeasonW
Average52
Games34
Challenge conversions
131→138
133→140
145→155
146→156
148→159
149→161
151→162
162→175
USBC standing
Memberships
AssociationGr Yellowstone Valley USBC
StatusCurrent
From2026-08-01
Through2027-07-31
AssociationHelena USBC
StatusCurrent
From2026-08-01
Through2027-07-31
AssociationGr Yellowstone Valley USBC
StatusPast
From2025-08-01
Through2026-07-31
AssociationIBC Youth HQ
StatusPast
From2025-08-01
Through2026-07-31
AssociationGr Yellowstone Valley USBC
StatusPast
From2024-08-01
Through2025-07-31
Show earlier memberships Hide earlier memberships
AssociationIBC Youth HQ
StatusPast
From2024-08-01
Through2025-07-31
AssociationGr Yellowstone Valley USBC
StatusPast
From2023-08-01
Through2024-07-31
AssociationGr Yellowstone Valley USBC
StatusPast
From2022-08-01
Through2023-07-31
AssociationGr Yellowstone Valley USBC
StatusPast
From2021-08-01
Through2022-07-31
AssociationGr Yellowstone Valley USBC
StatusPast
From2020-08-01
Through2021-07-31
AssociationGr Yellowstone Valley USBC
StatusPast
From2019-08-01
Through2020-07-31
AssociationGr Yellowstone Valley USBC
StatusPast
From2018-08-01
Through2019-07-31
AssociationGr Yellowstone Valley USBC
StatusPast
From2017-08-01
Through2018-07-31
AssociationGr Yellowstone Valley USBC
StatusPast
From2016-08-01
Through2017-07-31
AssociationGr Yellowstone Valley USBC
StatusPast
From2015-08-01
Through2016-07-31
Career milestones
Honors
0900 series
0800 series
0300 games
011 in a row
Tournament history
Open Championships
Adjusted entering average
154
How it was calculated
The highest sport-adjusted average from the last three bowling seasons is used until 27 Open Championship games are available.
2025/26177 → 154
Your Open Championships average is calculated from your 27 most recent games bowled between 2018 and 2026.
Search historical Open Championships scores.