Soot and ash from the fires affecting almost 5,000 square kilometres in Canada’s westernmost province were carried across the Atlantic by westerly winds, SRF Meteo said in statement.
The smoke from the fires in the province, where a state of emergency has been declared, took around three and a half days to reach Switzerland.
On Tuesday morning, fine particles of soot and ash – measuring just 2 to 3 microns across – filtered the sunlight causing red and yellow-tinged sunrises.
The same effect was seen in the evening.
Soot readings also shot up dramatically at the Jungfraujoch saddle in the Bernese Oberland, a popular tourist destination nearly 3,500 metres above sea level.
The phenomenon was also noted in the canton of Ticino on Sunday, according to government meteorological service MeteoSuisse.