בראשית, פרק ז׳, פסוק י״ז

The turning point of the Flood occurs when the sheer force of destruction transforms into a carrying power. As the rain continues to fall, the water accumulates into a massive body that reshapes the earth and eventually detaches the heavy Ark from the ground. The timeline of forty days is not a mere repetition of past events, but a clear explanation of cause and effect. It was precisely because the rain fell continuously for forty days and nights [רד״ק] that the water reached a level capable of lifting the Ark [חזקוני, ביאור יש״ר, קאסוטו, מלבי״ם]. During this specific period, the primary goal of wiping out all living creatures was achieved. Any destruction that occurred afterward was solely intended to ruin the earth itself [העמק דבר].

This period of forty days also carries deep symbolic meaning, directly corresponding to the severe sins of that generation. The people were guilty of idolatry, which is considered equivalent to denying the Torah that was given over forty days. They were also guilty of sexual immorality, which is mirrored by the forty days it takes for a human embryo to form [כלי יקר]. Some suggest that these days left a lasting spiritual mark on the world for all future generations [שפתי כהן]. Regarding the chronology, commentators debate whether the very first day of rain is included in the count of the forty days, a detail that shifts the exact date the rain ended in the Hebrew month of Kislev [הרא״ש, הטור הארוך].

Because the Ark was fully loaded and incredibly heavy, it did not float as soon as the rain began. The primary approach among commentators is that the Ark was submerged deep in the water, sitting eleven cubits low. As long as the water remained below this level, the immense weight of the Ark kept it firmly anchored to the ground. Only after forty days of accumulation did the water finally overcome the weight and lift the structure [רש״י, מזרחי, לבוש האורה, משכיל לדוד, שפתי חכמים, רש ר הירש, ביאור שטיינזלץ]. However, some caution against trying to mathematically calculate the exact rate at which the water rose. They argue that changing natural conditions, such as evaporation and varying mountain heights, make such simplistic calculations impossible [ברכת אשר על התורה].

The actual process of the Ark lifting off the ground happened in distinct stages. The floodwaters were a combination of fierce rain pouring from above and boiling groundwater bursting from below [אברבנאל, אלשיך]. Initially, this massive surge of water simply detached the Ark from the earth. At this stage, the Ark was lifted but remained in its original location. It was only later, as the waters swelled further beyond natural limits, that the Ark finally began to float and drift freely across the surface [רד״ק, מלבי״ם, אלשיך].