The thickness of the ice on Walden.

March 19.

P. M. — To Walden. 

Measure the snow again. West of railroad, 15; east of railroad, 11 4/5; average, 13 2/5; Trillium Woods, 16 3/4. 

The last measurement was on the 7th, when it averaged about sixteen inches in the open land. This depth it must have preserved, owing to the remarkably cold weather, till the 13th at least. So it chances that the snow was constantly sixteen inches deep, at least, on a level in open land, from January 13th to March 13th. 

It is remarkable how rapidly it has settled on the east of the railroad as compared with the west since the 7th (or I may say rather the 13th). The whole average settling, in open land, since say the 13th, is a little less than three inches. 

The thickness of the ice on Walden in the long cove on the south side, about five rods from shore, where the water is nineteen and a half feet deep, is just twenty six inches, about one foot being snow ice. In the middle it was twenty-four and a quarter on the 11th. It is the same there now, and undoubtedly it was then twenty six in the long cove. Probably got to be the thickest on this side. 

Since the warmer weather which began on the 13th, the snow, which was three or four inches deep, is about half melted on the ice, under the influence of the sun alone, and the ice is considerably softened within the last five days, thus suddenly, quite through, it being easier to cut and more moist, quite fine and white like snow in the hole, sticking together as damp snow when I shovel it out on my axe, the dust not at all hard, dry, and crystalline. 

Apparently, then, Walden is as thickly frozen about shore as Flint’s. 

While I am measuring, though it is quite warm, the air is filled with large, moist snowflakes, of the star form, which are rapidly concealing the very few bare spots on the railroad embankment. It is, indeed, a new snow-storm. 

Another old red maple bleeds now, on the warm south edge of Trillium Wood. The first maple was old and in a warm position.

No sooner is some opening made in the river, a square rod in area, where some brook or rill empties in, than the fishes apparently begin to seek it for light and warmth, and thus early, perchance, may become the prey of the fish hawk. They are seen to ripple the water, darting out as you approach. 

I noticed on the 18th that springy spot on the shore just above the railroad bridge, by the ash, which for a month has been bare for two or three feet, now enlarged to eight or ten feet in diameter. And in a few other places on the meadowy shore, e. g. just above mouth of Nut Meadow, I see great dimples in the deep snow, eight or ten feet over, betraying springs. 

There the pads (Nuphar) and cress already spring, and shells are left by the rat. At the broad ditch on the Corner road, opposite Bear Garden, the snowy crust had slumped or fallen in here and there, and, where the bridge was perfect, I saw it quite two feet thick. 

In the smooth open water there, small water-bugs were gyrating singly, not enough to play the game. 

I am surprised at the sudden change in the Walden ice within five days. In cutting a hole now, instead of hard, dry, transparent chips of ice, you make a fine white snow, very damp and adhering together, with but few chips in it. The ice has been affected throughout its twenty-six inches, though most, I should say, above. Hard to say exactly where the ice begins, under the two inches of snow.

H. D. Thoreau, Journal, March 19, 1856

No sooner is some opening made in the river, . . . than the fishes . . . ripple the water. . .  See March 18, 1856 (“I see the ripples made by some fishes, which were in the small opening at its mouth, making haste to hide themselves in the ice-covered river.”);March 19, 1854 (" You look into some clear, sandy-bottomed brook, where it spreads into a deeper bay, yet flowing cold from ice and snow not far off, and see, indistinctly poised over the sand on invisible fins, the outlines of a shiner, scarcely to be distinguished from the sands behind it as if it were transparent.”)