In the summer of 2013, Europe got affected by smoke from wildfires in North America. A haze was covering the sky, attenuating the incident solar radiation, at many places in Europe. Especially during two periods, high values of Aerosol Optical Depth (AOD) were detected by MODIS over Europe. In omit connection with these periods large aerosol concentrations were observed over the Atlantic, detected by OMPS. Periods concerned are from June 22 to 27 and from July 4 to 14. Research shows that the smoke was most likely due to large fires in Quebec. Sun photometers operated by AERONET showed an AOD of 1.9 in England on June 26 and 1.5 in Sweden on July 8. Ceilometers and LIDAR measurements detected the smoke in Belgium, The Netherlands, Sweden and Norway. All on an altitude of 2-4 km. In the area of interest, research shows that southern part of Norway was influenced by an AOD of approximately 1.1 on July 11 and 12. Simulations by WRF show that an AOD of 1.1 would have affected the surface temperature with 0.25-0.50 degrees. By comparison, an AOD of 10 would have affected the temperature by 1.7-1.9 degrees, which corresponds to a typical value of an altostratus cloud. At such high AOD values temperature effect become non-linear due to saturation effects.