The forces of nature, which typically serve to nourish the earth and balance the climate, can suddenly transform into instruments of divine justice. God actively holds back and stores elements like snow and hail, keeping them in reserve for designated moments when He must punish the wicked [רש״י, רלב״ג, ביאור שטיינזלץ]. When unleashed, these elements engage in a divine struggle, acting both as weapons for close, face-to-face combat and as projectiles for long-distance attacks [מלבי״ם, מצודת ציון].
The primary approach among commentators connects this storing of natural forces to specific historical and future events. During the plagues in Egypt, God stopped the falling hail in midair, suspending and preserving it for future times of distress and conflict. Years later, some of these massive hailstones were unleashed upon the five Amorite kings at the descent of Beth-horon during the days of Joshua. The remaining hailstones are still held in reserve, waiting for a future day of battle to be used against enemies in the ultimate war of Gog and Magog [רש״י, אבן עזרא, מצודת דוד, אלשיך].
Looking at this through a broader lens of divine providence, the natural world itself functions as God's armory. Snow-capped mountains act as towering fortresses from which God releases devastating avalanches and freezing blizzards to ruin the strongholds of the wicked, while hailstones serve as the arrows He rains down upon His enemies [מלבי״ם].
In contrast to these national and historical interpretations, another perspective views this struggle as an allegory for the daily life of an ordinary person. In this light, the time of distress and the day of battle do not refer to a military conflict at all. Instead, they represent the fierce, stormy days when a person is trapped indoors by snow and hail. During these turbulent times, the individual faces a deep internal struggle and profound fear, worrying anxiously that the harsh weather will destroy the crops in the field and ruin their livelihood [תקות אנוש].