Why glacial lakes are blue

The pulverized minerals settle at the bottom of the lake as sediments. Some of these sediments also known as rock flour are suspended in the water column. Although some people have suggested that the turquoise color of the glacial lake is as a result of the reflection of the blue of the sky by the water surface, this is not accurate. Sediments or rock flour are responsible for the blue color seen on most glacial lakes.

Rock flour is very light. They are often suspended in water column most of the time and support the most population of algae, making the water to appear green. However, algae are not responsible for the blue color of the lakes. When sunlight reflects on the rock flour that is suspended on the water column, the spectacular blue color is formed on the glacial lakes, the lakes are visible from aerial photos. I remember when we were in Antarctica asking why the snow and ice on the glaciers looked blue.

The answer was a bit too scientific for me; something to do with long and short wavelengths. I just nodded sagely. Oh yes I recall that. The rock flour explanation is far easier to understand. However in some more in-depth articles there was also discussion of wavelengths and what shades our eyes can see.

To be honest at that point my eyes glazed over. These glacial lakes are amazing, it is interesting to find out more about the science behind such stunning color. Nature always provides the best recipes for stunning landscapes. Nature really has a way with a paintbrush and rock flour. Lucky you to live so close to such stunning scenery.

Fascinating info … had no idea what caused the various shades of color to those lakes. Enjoy the rest of your summer. Fall is just around the corner. We are very fortunate to live here. Hope you and Al are well and enjoying your time as well. Fascinating, Sue! No, I had no idea that rock flour is responsible for the turquoise color of these magnificent lakes. Are all these photos yours? The lack of cloud cover surely is important to make the spectacular colors come out brilliantly.

Liesbet how wonderful that you have seen glacial lakes in so many locations! Yes all the photos were taken by Dave or I, well other than the last one of the two of us where we asked some to use my phone to do so. Sue, wow! Phenomenal photography and what an interesting post.

Thanks for the education. Like most, I suspect, we had never heard of glacial flour or of glacial milk. Love the description and my first thought was how fun it would be to run our toes in bright turqouise glacial silt. We have never seen a glacial lake, but now we most definitely want to. The color really is unbelievable. Wondering whether the water is too cold to swim in and whether people do swim in it?

When the fine particles mix with the glacial water, which is ice cold I will add, it causes more green and some blue to be reflected back to the eye making it look turquoise. In non glacial lakes, it is more blues that are reflected. This is a brief summary obviously. It really is quite a wonder. Thank you for the kind feedback on the photography. Very kind of you. I love any shade of blue and any body of water, but glacial lakes and rivers have to be near the top of my list!

Your Canadian gems are just one more impetus for me to get myself there asap! Thanks for the info, too — so interesting. How fabulous that you have seen glacial lakes in such far flung spots Lexie. We await your visit and know you would always be welcome here. Thanks for reading and glad to hear you found it interesting. I never knew….. Great and informative post Sue and stunning pictures!

Thanks for sharing!! Ahhh, this post brought back happy memories for me! Happy to take you back, albeit virtually, to these pretty lakes Diane.

We drive to Saskatchewan yesterday to see my Mom after not seeing her since January. Anyway…I purchased your second audio book for our road trip which made the drive much quicker. Now I wish I could be invisible too!

Oh, wow — thank you for supporting my audiobooks! I really appreciate that. Enjoy your visit with your Mom, and give her my best wishes. Hi Sue, I loved reading this and finding out why the water is so blue amongst other things! It fills a little hole, so thank you for making me smile this week.

A pleasure Debbie. Find out more in our Privacy Policy and Terms of Use. So why is Lake Pukaki so blue? Sorry, glacial flour? Is there a time of year the lake may appear brighter than other times? You may also be interested in ExploreCHC This place is a vast treasure trove of landscapes and experiences. Towering mountains give way to endless coastlines, rugged bush and unique land formations. Character towns and vibrant cities are gathering places of culture and activity.

We Want Adventure Get your blood pumping and experience thrills and epic activities. Vinebrooke took archival pictures of many lakes shot in the middle of the last century and compared them to modern images.

Even in the black-and-white of the earlier pictures, the change was evident. Then, the researchers took sediment cores from the bottom of the lakes. Their small glacier had melted. It also appears to have happened fairly quickly. Vinebrooke said a clear blue lake admits much more sunlight into depths than a lake clouded with glacial flour. Organisms adapted to the low light of milky waters are unlikely to survive what would be to them a harsh new glare of ultraviolet radiation.