What’s falling now — sleet or freezing rain? Here’s the difference

WASHINGTON - Snow transitioned to sleet for most of the D.C. area by Sunday afternoon. Several more hours of mixed precipitation is expected throughout the evening – including freezing rain for areas to the south and east. 

Sleet is expected to continue for several more hours on Sunday, with precipitation gradually tapering off between 8 and 10 p.m. across much of the region. Areas south and east of D.C. may see limited freezing rain. 

Sleet vs. frozen rain

Both sleet and freezing rain start with a snowflake that melts into a raindrop as it encounters a slice of warmer air on its free-fall through the atmosphere. But if there is a renewed area of freezing temperatures near the ground, the drop will refreeze. 

If the wedge of warm air is relatively narrow and the area of freezing air is fairly thick, the raindrop will have time to freeze back into an ice pellet. This is known as sleet (or on weather observations as "ice pellets" or "P").

Sleet can accumulate on the ground, but it is like stepping on zillions of tiny frozen raindrops.

Freezing rain comes when the wedge of warm air is relatively thick, and the area of freezing air hugging the ground is shallow. In this case, the raindrop doesn't have quite enough time to freeze into a solid but instead becomes "supercooled" to the cusp of freezing. 

Once it hits the surface, it will instantly freeze to wherever it landed. 

This process will result in freezing rain, or part of an "ice storm," and can be the most dangerous frozen precipitation. If you ever see a weather observation with the code "ZR," it's short for "freezing rain."

Unlike sleet, which is more of an accumulation of pellets, freezing rain creates an icy glaze and turns streets and sidewalks into increasingly-thick sheets of ice, making driving and walking quite treacherous.

What's worse, the ice is transparent, and many unsuspecting drivers can find themselves hurtling forward with no traction and no way to control their vehicle if they suddenly reach a road that was just hit by a freezing rain event. 

Freezing rain will also coat tree branches and power lines, and if enough weight accumulates, it can topple them both, leading to widespread power outages and tree damage.

Extreme cold from surge of Arctic air

What makes this storm particularly notable is the extreme cold that follows. Temperatures have remained well below freezing throughout the event and will stay there all week, preventing meaningful melting. Overnight lows will hold in the low to mid-20s initially, but another surge of Arctic air is expected to arrive by Tuesday morning, potentially driving temperatures into the single digits. At Reagan National Airport, a forecast low near 3 degrees could break a long-standing record set in 1935.

With daytime highs struggling to reach 20 degrees and overnight refreezing guaranteed, snow and ice are expected to persist for an extended period. FOX 5's Weather Team says this could mark the coldest sustained stretch of winter weather the region has experienced since 1989, making the longevity of icy conditions—rather than snowfall totals—the most impactful aspect of this storm as February begins.