A powerful winter storm struck the Front Range of Colorado March 13th and 14th, 2024, producing extremely heavy snowfall, difficult if not impossible travel conditions, and scattered power outages. While precipitation started in the form of snow in the mountains and foothills on March 13, it started as rain across the I-25 Corridor and plains.
Every event with a place to put it; 11 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS BOU wrote it up.
A powerful winter storm struck the Front Range of Colorado March 13th and 14th, 2024, producing extremely heavy snowfall, difficult if not impossible travel conditions, and scattered power outages. While precipitation started in the form of snow in the mountains and foothills on March 13, it started as rain across the I-25 Corridor and plains. That rain mixed with and changed to a heavy, wet snow across the Denver and Boulder metro areas during the late evening of the 13th. However, areas roughly along and east of a line from Fort Collins to Denver International Airport remained mostly rain or a rain snow mix until the early morning hours of March 14th. Some locations farther east like Greeley, Fort Morgan, and Limon didn’t changeover until late on the 14th. Total precipitation amounts in those areas and farther east across the plains were also much lighter. While there was a slight lull in the storm and snowfall rates on the morning of the 14th, snowfall rates increased again during the afternoon and early evening hours. The snow then tapered off during the late evening and overnight hours, and ended in the early morning of the 15th.
Difficult to impossible travel conditions started in the foothills shortly after the onset of heavy snow on the 13th. I-70 was closed, and dozens of vehicles became stuck and/or were abandoned. A ski bus full of 50 women ran out of food and water after being stuck for 16 hours. The depth of snow became so great that travel became impossible on unplowed roads for even high clearance or four-wheel drive vehicles. Some residents in the foothills were trapped for days in their homes. Also, numerous tree limbs snapped under the weight of snow, leading to scattered power outages. An estimated 113,000 customers were without power at some point during the storm, and that was before trees had even begun to leaf out for the spring! An estimated 800 flights were cancelled at Denver International Airport leading up to the snow, although fortunately the heaviest accumulations and impacts stayed just west of the airport. Widespread school closures occurred on the 14th and 15th from the Denver metro area into the foothills.
Storm total snow accumulations in the feet were observed across the foothills and east facing slopes of the Front Range mountains. Most areas above 6,000 feet westward to the crest of the Front Range (Medicine Bow Range, Rocky Mountain National Park, Indian Peaks and Mosquito Range) saw at least two feet of snow, while most of the foothills from Estes Park southward through Boulder, Gilpin, Clear Creek, and Jefferson Counties received in excess of three feet! A few spots saw from four to as much as five feet between Ward and Blackhawk, and also southeast of Idaho Springs (Beaver Brook neighborhood). The top five storm totals included: 61.5 inches in Aspen Springs, 61 inches, 5.4 miles northwest of Evergreen, 57.0 inches, 1 mile west of Aspen Springs, 54.4 inches near Rollinsville, and 53.7 inches, with 4.7 miles south-southeast of Idaho Springs. Colorado issued emergency disaster declarations for Clear Creek and Gilpin counties, due to the heavy amounts of snow, along with stranded motorists and residents. The main closures along Interstate 70 included: I-70 eastbound near Silver Plume, I-70 westbound in Georgetown, I-70 in both directions near Genesee, I-70 in both directions near Morrison, I-70 eastbound near East Frisco and Silverthorne, I-70 eastbound near Silverthorne and Loveland Pass. Nearly two dozen trucks were stuck along US 285, southwest of Denver, which resulted in its closure as well.
In the Denver metro area and Boulder, accumulations mostly ranged between 10 and 18 inches, with nearly two feet of snow from the southwestern sections of Boulder into the Golden area, extending southward through the far southern Denver suburbs into Douglas county and Castle Rock. There was a sharp gradient of snowfall to the east, with the far northeast sections of Denver - including DIA - receiving only 5 to 10 inches of snow. The official total at DIA was 5.7 inches. Similar amounts were seen farther north toward Firestone, Longmont, and the northeastern side of Fort Collins. At the National Weather Service Office in Boulder, 20.5 inches of snow was observed while only an inch or two of snow accumulated around Greeley, Fort Morgan, and Limon. On March 13th, 0.80 of rainfall was measured at Denver International Airport, which broke the daily record. The 2-day total, for March 13-14th, was 1.46 inches.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Denver/Boulder, CO wrote its last area forecast discussion before the first event at Mar 13, 11:00 AM MST, 0 minutes earlier. Its key messages:
Area Forecast Discussion National Weather Service Denver/Boulder CO 1200 PM MDT Wed Mar 13 2024 .KEY MESSAGES... - Travel may become impossible late tonight through Thursday night for locations in/near the Front Range mountains and foothills due to major winter storm. 2 to 4 feet expected in some foothill locations. - Difficult to nearly impossible travel conditions may develop in portions of the Boulder - western Denver suburbs - Monument Hill Corridor due to heavy, wet snowfall. A sharp west to east gradient in snowfall is expected, and thus there remains more uncertainty with regards to snow amounts in Fort Collins, Greeley, and I-70 east of Denver including Limon. - Scattered power outages are possible in areas of the Front Range that receive the heavier snowfall amounts. This will be a heavy, wet snow. - Snow will taper off Thursday night, into Friday morning, with gradual improvement in travel conditions (once the digout begins) Friday. - Localized strong downslope winds west of the Front Range including eastern Jackson and eastern Grand Counties. && .UPDATE... Issued at 1149 AM MDT Wed Mar 13 2024 Little change to the big picture as model trends continue to build confidence in the heavy snow event that begins later today. In particular, there's more aggressiveness about the late afternoon and evening convection and resulting heavy rain/snow and cooling temperatures. The convection allowing models typically overdo the intensity/coverage of the higher QPF amounts and are likely doing that this evening, but the idea of a round of vigorous showers and a few storms along with the resulting couple degrees extra cooling means there's a higher threat of getting heavy snow starting a few hours earlier this evening. Given the convection, this could vary some from one location to another. We'll be updating the forecast to hit this evening harder. It will likely still be mostly rain in the metro area in the early evening, but we've been saying 8 to 10 for the changeover and that still might be right, but roads could get slushy real quick when that happens--early evening lower foothills, mid evening Boulder/Golden or wherever the thunderstorms are. We're getting a burst of convection now out ahead of the main area of convection, so there may be a little mid afternoon break before the main event. We're also looking at a trend towards more snow Thursday evening as isentropic lift increases in southerly flow. This could boost snowfall on the plains in that time period, and provide several inches more than previously expected in Denver. But there may also be a break between the best upslope early Thursday and this southerly isentropic forcing late Thursday. At some point far enough west, these could just overlap, but not sure if that will be true for Boulder/foothills or not. && .SHORT TERM...(Today and tonight) Issued at 335 AM MDT Wed Mar 13 2024 Satellite shows the first lead shortwave pushing across the Front Range at this time, but slowly. That will continue to creep east/northeast into Nebraska. Meanwhile, another shortwave is moving into western Colorado, and this one will slow as it gets caught up in the main upper level trough closing off and digging southward into the Desert Southwest. That's the main storm system that will dig almost straight southward from Northern Idaho this morning to near Las Vegas by early Thursday morning. While this track is typically not favorable for a big snowstorm, there are other ingredients coming together for a significant March heavy snow event. First, the lead shortwave currently moving across our area is now forecast to be weaker, as mentioned in the previous forecast discussion. This will allow a more easterly component (more upslope) to develop in its wake, versus a more northerly component. This disturbance and weak lift has also pre-moistened the environment, with precipitable water values climbing well above normal and at nearly 2 standardized anomalies. That band of higher precipitable water will remain nearly locked in location through tonight, right across the northeast plains. Second, the more elongated mid/upper level trough (due to the weaker lead shortwave) will allow a stronger and deeper northeasterly upslope flow to develop than what would normally be realized in such a synoptic pattern. There's reasonable agreement that we'll see a period of deep 30 knot upslope develop as we move through the overnight hours and into Thursday morning. It seems odd given the pattern, but even the EC is showing a similar scenario unfold. Third, we're quite unstable with nearly neutral lapse rates through tonight. In fact, we'll even have 100-200 J/kg of MLCAPE around this afternoon and early evening for a couple thunderstorms. Thus, despite the "inordinary" pattern, we'll likely see the ingredients favorable for sustained upslope and heavy snowfall. One question that remains is how cold it will be and thus when rain changes over to snow. Showers are expected to become more numerous this afternoon as the second shortwave mentioned earlier pushes slowly east into our forecast area. Those will then likely intensify and become more widespread this evening as upslope flow develops and strengthens. While temperatures will be relatively mild and mostly rain below 6,000 feet through the day, we do think the combination of heavier precipitation rates and diabatic cooling along with upslope and weak cold advection from the north will be able to switch things over to snow across most of the Boulder - Denver corridor between 8 and 10 pm this evening. That said, that's if precipitation rates are high enough, which we do expect given the instability. It's farther east and northeast where there's considerably more uncertainty over the plains and even the northern I-25 Corridor around Fort Collins. Even DIA could be on the edge of heavier snowfall or slower transition from rain to snow later this evening and overnight. Thus, we've kept the Winter Storm Watches in place for the Fort Collins to Greeley to Limon Corridor. More on this in the Long Term Discussion below. All other highlights are unchanged at this time and on course. Regarding impacts, it would not be wise to attempt to drive in the foothills or Front Range mountains starting late this afternoon or evening as heavier precipitation develops. Given the ingredients, we think 2-3 inch per hour snowfall rates would be possible at times. Thus, rapid deterioration is expected with the onset of heavy snow. The same may be said even for the western Denver suburbs starting around 8-9 pm, or once the changeover occurs, although peak snowfall rates should be closer to 1-2 inches per hour given less terrain forcing. What could go wrong in this forecast? Rain/snow changeover being later. Intensities lower due to less upslope than models suggest, snow ratios being lower due to heavy, wet snowfall (and I admit not perfect dendritic growth regime). We did lower snow ratios from model/NBM guidance for this reason, but still ended up with impressive amounts! The deeper moisture shifting farther south - there has been a slight trend over the last 24 hours. Still, our confidence is high for a major winter storm in/near the Front Range mountains and foothills starting in the mountains and foothills mid to late afternoon, and then in the Denver/Boulder areas sometime this evening. This long duration storm continues through Thursday before letting up Thursday night...more on that below. Finally, we expect locally strong downslope winds on the lee side (west) of the Front Range. That's due to the relatively strong easterly component (30-35 knots), and a mean state critical layer. We're not entirely sure how this unfolds given the rarity of event, but some potential for strong east winds making their way down to Fraser and Grand Lake. We've adjusted the forecast winds in those areas to account for this potential of gusts to 40-60 mph. .LONG TERM...(Thursday through Tuesday) Issued at 335 AM MDT Wed Mar 13 2024 On Thursday the closed upper low will be centered near southern NV at 12z, with deep and moist northeast upslope flow from the surface to around 500 mb. The models show a period of light mid- upper level QG ascent through the day. The ECMWF/GFS shows a persistent northeasterly upslope flow of 25-30 kts through 00z Friday, as the closed low remains nearly stationary. Moist adiabatic lapse rates will prevail Thursday, with the best instability from the surface to 700 mb. The upslope appears get disrupted aoa 700 mb as a short wave trough passes out of Montana into the Upper Midwest Thursday evening. However below 700 mb, a weaker northeasterly upslope component will continue along the Front Range. Overall the snow then intensity of snowfall is expected to decrease Thursday night into Friday morning. Looking at the QPF/snow amounts, the models continue to hammer areas in and near Front Range Mountains, Foothills and Palmer Divide Thursday into Thursday night. The models still generate storm totals in excess of 40 inches in some areas. Overall the higher qpf amounts across northeast Colorado have been trending more the west and south, so the qpf is a little lower over the northeast plains. There is still questions as well regarding how much snow will occur in zones 38 and 43 where some decent northeast (downslope) winds off the Cheyenne Ridge are expected. For zones 45 and 46, confidence in the warning for these zones is higher vs zones 38 and 43. Strong winds over the Palmer Divide in particular may be flirting with borderline blizzard criteria at times on Thursday. It unusual to see an amplified mountain wave and mean state critical layer setup with downslope winds from east to west over the mountains, but that appears to be the case. Gusty northeast winds in the 50-60 mph range will likely occur on the exposed west facing slopes of the the Continental Divide through midday Thursday, then the wave should start to weaken in the afternoon. By Friday, the closed low will still be over the Desert Southwest, with a deformation axis at 500 mb oriented from southeast to northwest across CO. Northeast CO will remain under the dry and subsident side of the deformation zone parked over CO. The closed low is progged to remain parked in that region over the weekend as an omega ridge builds into British Columbia on Saturday. As it does, northern CO will be under an increasing northerly flow as an upper level jet passes across the Northern Plains and into the upper Midwest. This energy will be rotating around a long wave trough over the Great Lakes region. There may be some light snow showers in the mountains over the weekend but the plains should remain dry with just a gradual warming trend expected. By early next week, a mean ridge will be over the West. The closed low over the Desert Southwest finally weakens and washes out across CO by midweek. High temperatures will finally make it back into the mid 50s on Monday and into the 60s for Tuesday and Wednesday. && .AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon) Issued at 1149 AM MDT Wed Mar 13 2024 Updated for lower ceilings this afternoon. ILS approaches to KDEN will be needed with areas of MVFR ceilings and scattered rain showers this afternoon. More widespread rain will develop 22z-02z with isolated thunderstorms, then rain will change to snow by 04z. Areas of IFR are expected after 00z, with widespread IFR/LIFR in moderate to heavy snow after 04z. Snow will continue at the Denver terminals into Thursday night. Current storm total snow forecasts are 8-12 inches at KDEN, and 12-20 inches at KAPA/KBJC. && .BOU WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until 6 PM MDT Thursday for COZ031. Winter Storm Warning until 6 AM MDT Friday for COZ033>037. Winter Storm Watch from late tonight through late Thursday night for COZ038-043-045-046. Winter Storm Warning from 9 PM this evening to 6 AM MDT Friday for COZ039>041. && UPDATE...Gimmestad SHORT TERM...Barjenbruch LONG TERM...Cooper AVIATION...Gimmestad
Hazardous Weather Outlook National Weather Service Denver/Boulder CO 1125 AM MDT Wed Mar 13 2024 COZ030>051-141730- Jackson County Below 9000 Feet- West Jackson and West Grand Counties Above 9000 Feet- Grand and Summit Counties Below 9000 Feet- South and East Jackson/Larimer/North and Northeast Grand/ Northwest Boulder Counties Above 9000 Feet- South and Southeast Grand/West Central and Southwest Boulder/ Gilpin/Clear Creek/Summit/North and West Park Counties Above 9000 Feet-Larimer and Boulder Counties Between 6000 and 9000 Feet- Jefferson and West Douglas Counties Above 6000 Feet/Gilpin/Clear Creek/Northeast Park Counties Below 9000 Feet- Central and Southeast Park County- Larimer County Below 6000 Feet/Northwest Weld County- Boulder And Jefferson Counties Below 6000 Feet/West Broomfield County- North Douglas County Below 6000 Feet/Denver/West Adams and Arapahoe Counties/East Broomfield County- Elbert/Central and East Douglas Counties Above 6000 Feet- Northeast Weld County-Central and South Weld County-Morgan County- Central and East Adams and Arapahoe Counties- North and Northeast Elbert County Below 6000 Feet/North Lincoln County- Southeast Elbert County Below 6000 Feet/South Lincoln County- Logan County-Washington County-Sedgwick County-Phillips County- 1125 AM MDT Wed Mar 13 2024 ...MAJOR WINTER STORM BEGINNING THIS AFTERNOON IN THE MOUNTAINS AND FOOTHILLS AND THIS EVENING IN THE DENVER METRO AREA... This hazardous weather outlook is for northeast and north central Colorado. .DAY ONE...This Afternoon and Tonight Heavy snow will develop over the mountains and in the Front Range foothills this afternoon. Showers and thunderstorms will spread off the mountains onto the nearby plains in the late afternoon hours. Initially, the snow level will be between 6 and 7 thousand feet. Road conditions will deteriorate quickly in the Front Range mountains and foothills in the mid to late afternoon hours. Lower elevations will start with rain, but the snow level will lower to 5000 feet by mid evening. In Denver, Douglas county, and in areas near the foothills, rain will change to heavy snow over a few hours during the evening, with roads becoming slushy due to heavy snowfall rates of up to 3 inches per hour. Overnight a steady moderate to heavy snow is expected in and near the foothills, with rain changing to light snow in area further east. Plan on difficult to impossible travel after late afternoon in the Front Range mountains and foothills, and after mid evening along the I-25 Corridor. After these times, only travel in and emergency, and be sure to take along a winter survival kit in case you become stranded. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday The winter storm will impact the region through Thursday night, then a gradual improvement is expected on Friday. This storm will bring very heavy snowfall to to the Front Range mountains and foothills with anywhere from 18 inches to as much as 4 feet of snow expected. Travel will likely be impossible on side roads and very difficult on main highways in the Front Range mountains and foothills. Heavy snow will impact the Denver metro, Palmer Divide, and the rest of the I-25 corridor Thursday into Thursday night. One to two feet of snow is likely over the Palmer Divide, and 8 to 20 inches possible around metro Denver. The snow will taper off early Friday. On the plains, steady snow is expected Thursday into Thursday evening. While it will mostly be light, a period of heavier snow is possible from the afternoon into the evening. East of Fort Morgan and Limon, total accumulations of 1 to 3 inches are expected, with a strong gradient into heavier amounts going west towards the I-25 corridor. .SPOTTER INFORMATION STATEMENT... Snowfall reports will be appreciated. Gimmestad
The national radar mosaic for the moment the first event began.
8 winter storm, 3 winter weather. Local standard time, as filed.
Storm totals included: 53 inches, 4 miles east-northeast of Nederland, 46 inches at Eldora Ski Area, and 40 inches near Pennock Pass.
Storm totals included: 40.5 inches at St Mary's Glacier, 36 inches near Silverthorne, 28 inches at Breckenridge, and 25.0 inches in Frisco.
Some storm totals included: 53.0 inches, 4 miles east-northeast of Nederland; 46.0 inches at Eldora Ski Area, 45.9 inches, 4.6 miles northeast of Ward; 45.5 inches, 3 miles west of Jamestown; 41.1 inches near Estes Park, and 36.9 inches near Glen Haven.
Storm totals included: 61.5 inches in Aspen Springs, 61.0 inches, 5.4 miles northwest of Evergreen; 54.4 inches near Rollinsville, 53.7 inches, 4.7 miles south-southeast of Idaho Springs; 50.7 inches, 4 miles south-southeast of Pinecliffe, 45.7 inches near Genesee, and 45.0 inches near Aspen Park.
Storm totals included: 36.5 inches near Guffey, 27.0 inches at Highland Park, with 20.0 inches near Antero Junction and Fairplay.
Storm totals included: 26.0 inches near Lakewood, 23.0 inches near Louisville, 22.0 inches near Lafayette, 21.3 inches near Superior, 21.0 inches near Arvada, Broomfield and Lakewood; and 20.5 inches at the National Weather Service in Boulder.
Storm totals included: 16.1 inches, 5 miles south-southeast of Denver, 15.8 inches near Cherry Hills Village; 11.0 inches, 4 miles east of Denver, 10.0 inches at Denver Botanical Gardens, with 5.7 inches at Denver International Airport.
Storm totals included: 33.2 inches near Kassler, 30.0 inches near Roxborough Park, 28.3 inches near Castle Pines, 28.0 inches, 3.5 miles south-southeast of Sedalia; 25.7 inches near Castle Rock, 24.5 inches near Lone Tree, 24.2 inches near Highlands Ranch and 22.3 inches near Parker.
Storm totals ranged from 5 to 12 inches in and around Fort Collins and Loveland.
Storm totals generally ranged from 2 to 5 inches, except 6 to 10.5 inches around Erie and Frederick.
Storm totals up to 5 inches were observed around Bennett and Byers.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Colorado in 2024Every state in 2024This day in weather historyWarnings in Colorado, March 2024
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 1156368, 1156369, 1156370, 1156371, 1156372, 1156373, 1156374, 1156375, 1156376, 1156377, 1156378.