The sky, naturally intended to be a source of life and growth, can tragically reverse its role and become an agent of destruction. In a harsh paradox of nature, a falling shower brings dust rather than water. The concept of rain in this context does not necessarily imply water, but rather the simple action of a substance falling from above [רשב״ם].
The primary approach among commentators is that this disaster stems from severe dryness, heat, and fierce winds. Instead of nourishing moisture, powerful gusts sweep in carrying sand and dirt, creating the exact opposite of life-giving precipitation [אבן עזרא, שד״ל, ביאור שטיינזלץ, פירושן של נשים]. These violent winds strip dust from high, dry mountain peaks and possess enough force to uproot trees [חזקוני, ביאור יש״ר]. Another perspective suggests that the water vapors in the air themselves transform into thick smoke and harmful dust, damaging both plant and animal life [רלב״ג].
A different approach addresses the contradiction between water and dust by suggesting the curse occurs specifically when a small amount of rain does fall. Because the light rainfall is insufficient to settle the loose earth, a sudden strong wind whips the dirt into the air. This airborne dust then clings to the damp crops and grass, forming a layer of mud. As the mud dries, it causes the vegetation to rot and die [רש״י, בכור שור, רש״ר הירש]. Although the dirt originates from the ground, the winds carry it to such great heights that it appears to fall directly from the sky itself [תורה תמימה, רש״ר הירש].
The resulting destruction of the crops leads to severe famine. The lack of food forces the population to wander from their homes in search of sustenance, leading to widespread death [העמק דבר]. However, some view the language of total destruction as an expression meant to emphasize the sheer intensity, persistence, and massive ruin of the disaster. It does not imply the absolute and immediate end of the entire nation, as further hardships continue to follow [ביאור יש״ר].