Developing analysis · Record 001
Dome Fire,
Yosemite.
A dated record of the official figures, the documented fire-behaviour signals and the evidence still needed—without turning a changing incident into false certainty.
Editorial review: · Version 6
Latest snapshot
What changed.
The CAL FIRE incident update at 7:07 AM on 28 September reports 5,215 acres and 30% containment. Its 27 September entries reported 4,809 acres and 30% at 7:19 AM, then 5,084 acres at 11:48 AM without a new containment figure. The NPS morning report on 27 September also listed 4,809 acres, 30% and 781 personnel. Those are dated agency snapshots, not a single continuous measurement.
This snapshot is anchored to the 28 September 2026 CAL FIRE incident update. The 27 September NPS report supplies dated operational context, including 781 personnel. Check live official sources for newer conditions.
Technical reading
Signals worth following.
The 18 September bulletin reports slower activity in previous burns and wind-driven spotting to the north. These dated observations frame the editorial questions below; they do not describe current conditions everywhere.
Overlay dated perimeters and previous burn boundaries. A local observation should not be extended to the whole perimeter without that comparison.
Which ignitions can be matched to a timestamp and position? This record has no validated spotting-distance dataset.
An assessment would need crew access, timing and operational records before attributing outcomes to a particular constraint.
Incident acreage does not measure exposure at a reader’s location. Use current official local observations and instructions.
Learn more: what is wildfire spotting and how do spot fires form? →
Fatal firefighting helicopter crash
On 20 September, a contract firefighting helicopter crashed during water-drop operations on the Dome Fire near Ostrander Lake. The two pilots aboard, Greg King and Ryan Cutter, were killed. The aircraft was an AS332 Super Puma operated by Precision.
The Federal Aviation Administration states that the helicopter crashed at about 2:55 PM local time during firefighting operations in Mariposa County. The cause has not been determined; the National Transportation Safety Board and FAA are investigating. Tecnobosque will not speculate about a mechanical, operational or environmental cause until investigators publish evidence.
Why this belongs in the record: aviation was part of the suppression system documented for the Dome Fire, and the crash materially changed the incident’s human and operational history. It is recorded separately from fire-behavior interpretation.
Open the dedicated Dome Fire helicopter crash record →
Observation is not prediction
A reported spot fire is evidence of an observed event. It is not, by itself, a forecast of where the perimeter will move next. Tecnobosque does not publish a spread forecast for this incident.
Evolution of knowledge
The source chronology.
Initial public figure; moderate rate of spread reported.
Grass, brush and timber fuels; upslope movement aligned with terrain and wind.
Active overnight burning; limited access and steep terrain noted.
Upslope runs and short-range spotting reported.
First published 15% containment figure in this chronology.
Area revised; no new containment value published in that entry.
Updated official area.
Updated official area.
Incident-log figure preserved from Version 2.
National Park Service morning update; 581 personnel reported.
CAL FIRE active-index snapshot preserved from Version 3.
National Park Service operational update.
CAL FIRE active-incidents index value at editorial review.
National Park Service morning update.
National Park Service morning update; 240-acre increase since the previous morning.
NPS morning report also listed the same area and containment, with 781 personnel.
New area reported; no revised containment percentage in this entry.
Latest reviewed incident update for this version.
Visitor impact
What Yosemite visitors should know.
In its 27 September morning update, the National Park Service said Yosemite National Park remained open and operating normally with specific fire-related exceptions. NPS also reported no roads, buildings or utilities under immediate threat in that dated update.
Yosemite remained open and operating normally with specific fire-related exceptions in the 27 September NPS update.
Chilnualna Falls Trail, routes toward Buena Vista and Crescent Lakes, Ostrander Trail and additional areas south of it were closed in the dated NPS update.
Glacier Point Road was closed because of reduced visibility from smoke and to support firefighting operations. NPS said it would reopen when conditions allow.
The 27 September outlook ranged from good in several locations to moderate in Yosemite Valley and unhealthy for sensitive groups in Tuolumne Meadows. Check current observations before travel.
Evidence discipline
What remains unknown.
A developing record is useful only when missing evidence remains visible. Version 6 does not fill these gaps with estimates.
- Comparable timestamped perimeter files sufficient for a spatial growth analysis.
- Incident-specific weather observations aligned with each mapped interval.
- A checked spatial comparison with the 2017 Empire Fire and other previous burn footprints.
- A complete, current inventory of access restrictions and visitor impacts.
- CAL FIRE now lists “Campfire” in its 28 September cause field. NPS described an investigation as ongoing on 21 September. This record has not reviewed a final investigative report establishing mechanism, source or legal responsibility; the dated source statements are preserved separately.
Provenance
Sources and release.
- CAL FIRE — Dome Fire incident page and dated updates ↗Primary incident page reviewed for the 28 September 7:07 AM status update, chronology and current “Campfire” cause field. The field is not treated as a reviewed investigative report.
- InciWeb — Dome Fire incident information ↗Official federal incident route linked by CAL FIRE. Readers should use the live page for its current state.\n
- National Park Service — Dome Fire update, 26 September 2026 ↗Earlier dated operational and visitor snapshot.
- National Park Service — Dome Fire update, 27 September 2026 ↗Operational and visitor snapshot: 4,809 acres, 30%, 781 personnel and dated closures.
Version history
Version 6 · 28 September 2026: added CAL FIRE’s 5,215-acre / 30% report at 7:07 AM, preserved two 27 September updates and NPS operational context, refreshed the dated visitor section, and attributed CAL FIRE’s “Campfire” field while retaining the earlier NPS investigation status as a separate source statement.
Version 5 · 28 September 2026: updated the current snapshot to the 26 September NPS morning report: 4,498 acres, 28% containment and 781 personnel; refreshed Yosemite visitor information and added 25–26 September chronology entries.
Version 4 · 24 September 2026: updated the current reviewed snapshot to 3,989 acres and 15% containment; added the 23 September NPS 3,795-acre / 840-personnel operational snapshot while preserving source timing.
Version 3 · 22 September 2026: updated the current reviewed snapshot to 3,420 acres and 15% containment from the CAL FIRE active-incidents index; added the 21 September NPS 3,222-acre snapshot so the source timing remains visible.
Version 2 · 21 September 2026: updated the reported area from 2,384 to 3,047 acres; preserved 15% as the displayed containment figure; expanded the official chronology; added dated visitor-impact and closure context from the National Park Service; clarified previous-burn, spotting and uncertainty language; and rebuilt the mobile/desktop first viewport.
Version 1 · 20 September 2026: initial sourced snapshot and editorial questions.
This permanent URL retains the record while material revisions state what changed.
From evidence to preparation
Use the incident to ask better questions.
These tools use the reader’s own inputs. They do not measure, predict or advise on conditions around the Dome Fire.