The seasonal algae bloom on Lake of the Woods is underway and has progressed up into the north end of the lake, as shown in the collage of derived chlorophyll-a data for Sept 26 through Oct 5 (data imaged courtesy of EOLakeWatch, Dr. Caren Binding ECCC). The bloom has progressed through the northern part of the lake to the Kenora area, and as can be seen in the Chl-a data for October 4 and 5, the bloom is even present in the Ptarmigan channel / bay area of the "Clearwater" complex of bays.
However, the blooms in these lower nutrient isolated bays may be a result of the strong shift in winds from the north to easterlies and then strong southerlies in the Oct 3 - 4 period causing flowage of surface blooms from the central waters well into these areas. Likely, the effect of wind can be seen also in the southern Big Traverse basin of the lake with the heavy bloom shifting from the south-east to the north-west part of the Big Traverse and with the dark red (highest Chl-a) shrinking. The shrinking of the high Chl-a red "hot spots" is consistent with mixing of the water and algae down into the water column -- remember, the satellite images are detecting and computing data for the blooms on the surface only.
Blue green algae (cyanobacteria) scum near Kenora, September 29, 2021. Click to enlargeHeavy blue-green algae blooms have been apparent in waters near Kenora in recent weeks, as shown in these pictures or surface scums taken on Sept 29. Although for much of the summer, it seemed like a "light year" for algae blooms, significant blooms began to develop towards the end of August and are continuing to strenghten into October. The low blooms in much of the mid-summer may perhaps be due to the low water and low flows from the nutrient-rich southern basin of Lake of the Woods, or perhaps lower light conditions due to the intense smoke that blanketed the lake throughout July and into the first week of August.