Montevideo, Uraguay, October 1958October 1958

Insufficient Data

Summary

On October 15, 1958, at 1025 (10:25 a.m.), multiple people in Montevideo, Uruguay saw a bright ball of fire cross the sky. The object was followed by an opaque, whitish trail of smoke. According to newspaper accounts, it moved over the city several times, circling back on itself rather than traveling in a straight line.

The sighting was witnessed by a reporter and photographer from the newspaper Acción, as well as schoolchildren on recreation break and other civilians at Independence Square and Matriz Square. Because of the object's unusual movement pattern, circling and returning over the same area multiple times, witnesses ruled out explanations such as a satellite or meteorite, which would travel in straight lines. One account mentions the object appeared to move roughly ten minutes, with its front end moving back and forth in a crossing pattern.

The Uruguayan Meteorological Service investigated the sighting and concluded the phenomenon was likely caused by a jet aircraft flying at very high altitude, between 12,000 and 15,000 meters (roughly 39,000 to 49,000 feet). At those heights, the jet's engine exhaust condenses immediately upon leaving the nozzle, creating the white contrails (condensation trails) that witnesses saw. The service noted that Uruguayan Air Force jets were conducting routine flight operations in the area at the time of the sighting. The Air Force evaluated the case as unknown.

The full case file is reproduced below as held by the National Archives, comprising 10 pages of original documents.

Reported location

Montevideo, Uraguay, October 1958

Date of incident

October 1958

State / country

? / XX

Page count

10 scanned pages

USAF evaluation

unknown

Microfilm

T1206, Roll 34

: ; i Na ——— : » ee " . = ; oo ET ‘ PROJECT 10073 RECORD CARD ’ 8 : 1. DATE : 2. LOCATION 12. CONCLUSIONS ; 3 : 0 Was Balloon { 15 Cotobar 105 Montovidio Ueuosunv O Probably Balloon 3 3. DATE-TIME GROUP 4. TYPE OF OBSERVATION br Hocsvbly Bolloon : REE *D-Ground- Visual DO Ground-Rador i Noe bumps oft : 3 PT pli S07 4F 40 10% 6 VAN 0 Air Visual O Air-Intercept Radar D Possibly Aircraft : | : 5. "PHOTOS : 6. SOURCE O Was Astronomical : ; a Yes : D Probably Astronomical 4 No Civilian s) Possibly Astronomical : 7. LENGTH OF OBSERVATION 8. NUMBER OF OBJECTS | 9. COURSE ~~ | oOther = i : ; : |o insufficient Dota for Evaluation i . 2 rel s ; BO Unknown . Z not rptd ona reversed Casati ; 8 10. BRIEF SUMMARY OF SIGHTING ~ |11. COMMENTS | ! H i 1 0] 1 <5 e GR : 3 Unusually bright hall of fire folliowe Evaluated as a possible a/c by § by a smoke trail whitish & opaque the Meteorological Service of g observed by many people in Uruguay. Uruguay. Obj moved over area Newspaper article rptd that the obj | several times leaving smoke : : passed oer the city several times. trails (contrails). : A/C rptd in area (jets). 3 ATIC FORM 329 (REV 26 SEP 52) - ; A | : 3 Lo ; 2