A prolonged period of heavy snowfall during the first week of March produced historic avalanche conditions across the northern and central mountains of Colorado. Mountain highways including a large section of I-70 was closed on the 7th due to high to extreme avalanche danger.
Every event with a place to put it; 5 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 prolonged period of heavy snowfall during the first week of March produced historic avalanche conditions across the northern and central mountains of Colorado. Mountain highways including a large section of I-70 was closed on the 7th due to high to extreme avalanche danger. The snow was heaviest during the overnight hours when a concentrated band of heavy snow remained stationary over a large stretch of the Interstate 70 corridor, producing snowfall rates up to 2 inches per hour. Storm totals included: 24 inches near Mount Zirkel; 17 inches near Loveland Pass; 15.5 inches near Berthoud Falls; 15 inches near Silverthorne; 14.5 inches near Climax; 13 inches near Cameron Pass, Glendevey, Longs Peak and Mount Audubon; 12 inches near Alma, Gould and Guanella Pass; 11 inches near Frisco; with 6 to 10 inches elsewhere.
An avalanche that ruptured a natural gas line behind the Conoco station at Copper Mountain; and several other avalanches led to the closure of I-70 in both directions between Copper Mountain and Vail. The ruptured gas line created a power outage at the Eisenhower Tunnel. Colorado Department of Transportation (CDOT) crews were escorting 100 vehicles through the tunnel when the outage occurred. Interstate 70 between Silverthorne and Empire Junction was closed for about three hours in the area for avalanche mitigation. Arapahoe Basin ski area did not open on the 7th because of high avalanche danger on nearby Loveland Pass. The Colorado Avalanche Information Center deemed several of the backcountry zones EXTREME (5 of 5), including Vail and Summit County. This was the first time this designation has been used since they converted to a ten-zone forecast format back in 2006. The warning comes after multiple avalanches over the previous weekend and an avalanche that has shut down Interstate 70 between Frisco and Vail early on the morning of the 7th.
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 6, 10:47 AM MST, 3 hours 13 minutes earlier.
Area Forecast Discussion National Weather Service Denver/Boulder CO 1047 AM MST Wed Mar 6 2019 .UPDATE... Issued at 1011 AM MST Wed Mar 6 2019 Satellite imagery shows a cloud shield with better moisture content and colder cloud tops moving over the northern Colorado mountains this morning. In addition, radar returns from Grand Junction and Denver are increasing over the same region. Therefore, I increased POPs and QPF slightly but, for the most part, they were within reason. Models still are showing a heavier band or two that could produce heavy snowfall rates up to 2 inches per hour this evening over the mountains. We want to emphasize that travel will likely be hazardous this evening in the mountains because of the snowfall throughout the day and the potential for high snow rates within the snow bands this evening. With the slight increase in snow totals today and this evening, the areas currently under a Winter Weather Advisory may be close to reaching Winter Storm Warning criteria. However, we have kept the Advisory because outside of the potential heavy snowfall this evening, snowfall rates won't be terribly heavy. Across the urban corridor and plains, I increased POPs to indicate a slight chance of rain, snow, or freezing drizzle this evening mainly over the Denver metro. That's to give people a heads up there may be some precipitation tonight but I do think the HRRR is overdoing the showers that come off the mountains. Most models keep these areas mainly dry tonight so no QPF was added. && .SHORT TERM...(Today and tonight) Issued at 415 AM MST Wed Mar 6 2019 Challenges all around again, including heavy mountain snow, temperatures on the plains, and a chance of light snow showers and even a bit of light freezing rain on the plains tonight. Current satellite shows several waves of rich subtropical moisture streaming northeast off the Pacific and across the Great Basin. The first wave associated with warm advection already pushed north of the forecast area, but brought light snow to the northern mountains. The second wave is arriving in these early morning hours, and there will be an uptick in mountain snow with this. Another wave or two may arrive trough the course of the afternoon, but the main show with heavy snowfall is expected to occur in the northern mountains this evening as a cold front combines with very strong mid level flow and embedded convection. Snowfall rates may jump to 2 inches per hour for a couple hours with the passage of the front. That should hit the I-70 Mountain Corridor through Summit County toward 8 PM - Midnight. The heavy snow will likely be accompanied by strong winds (gusts to 60 mph or more above timberline) to create poor visibility and difficult driving conditions. Until then, very strong warm advection occurs and we will see some valley rainfall, with snow levels rising to near 9000 feet for the afternoon. Those will come crashing back to valley floors this evening with the arrival of the cold front and heavier precipitation rates. We may have to upgrade to Winter Storm Warnings in the Front Range Mountains including the I-70 Mountain Corridor. On the plains, there will likely be enough instability and forcing with the frontal passage aloft this evening to bring a band of showers into the lower elevations. Model cross sections all show a warm nose of +4 to +6C shooting over the top of the shallow arctic air which will be difficult to erode with no lee troughing and upper level cloudiness today. As a result, if the showers do come out we will have a threat of brief light freezing rain. We'll have to watch that for any potential impacts to late evening travel, but coverage and precip amounts look limited. Finally, regarding today's highs...we've nudged down temps north of Denver with a shallow easterly flow likely holding the arctic airmass in place. Clouds above this also won't help warming. Farther south, on the Palmer Divide, there's potential we push through the 50s and even approach 60F if we can get enough sunshine as enough southerly flow exists there to erode the arctic air. The increased baroclinicity between the warm to the south and cold north will likely drive a Denver Cyclone, which would also reinforce the easterly component and cooler temps to the north. Denver metro could very well be on the border of this through the day, with much colder temperatures over the northern suburbs versus the southern suburbs and Douglas County. .LONG TERM...(Thursday through Tuesday) Issued at 415 AM MST Wed Mar 6 2019 A progressive flow pattern across the western United States will bring a series of weather disturbances to Colorado over the next several days. Satellite imagery shows a decent amount of moisture has come onshore over central and southern California which will be making its way to Colorado over the next few days. The tail end of the first surge of moisture is expected to be over the mountains through midday Thursday. After that, a short wave ridge will build over the state that diminishes the snowfall over the mountains. Each of the medium range models show this break in mountain precipitation developing by Thursday evening which is when the current set of highlights runs to. Dry conditions will prevail across the plains through Thursday night. On Friday, moisture ahead of the next developing upper trough is expected to reach the mountains. This next trough is forecast to have more amplitude which will affect its strength and also prolong how long it takes to move across the state. Light to moderate snow should develop in the mountains by Friday afternoon and continue into Saturday morning. Surface cyclogenesis is forecast over eastern Colorado with this trough which will help draw low level moisture over the plains. With the dynamics of the upper trough passage Friday night and Saturday morning, a round of precipitation will be possible across the plains. Warm temperatures initially mean that rain showers and then a mix of rain and snow will be possible overnight. By Saturday morning, precipitation should have switched over to snow as the system is moving out. Behind this upper trough, models are showing strong subsidence which will produce gusty winds over the foothills and out onto the plains through the day Saturday. From Sunday into Monday, each of the models show a flat upper ridge over Colorado which should bring some relief from the mountain snowfall and mild temperatures on the northeast Colorado plains. The medium range models have a variety of solutions on Monday and Tuesday concerning the development, strength and timing of a possible cutoff low over the desert southwest. Will not spend too much time trying to decide which solution is right. The end effect for northeast Colorado is dry weather through the first half of the week. && .AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon) Issued at 1011 AM MST Wed Mar 6 2019 VFR conditions should prevail through the late afternoon. The biggest forecast challenge is this evening when a few showers may move off the mountains and affect the airports. Ceilings should lower with possible MVFR from the passing showers. There is a small threat of light freezing rain as cold air undercuts the warmer air aloft but chances remain small for this occurring. The main concern for this would be from 03Z- 07Z. Beyond 07Z, conditions should be dry. By late morning tomorrow, stronger westerly winds will likely form at all three airports. && .BOU WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until 5 PM MST Thursday for COZ033-034. Winter Storm Warning until 5 PM MST Thursday for COZ031. && UPDATE...Danielson SHORT TERM...Barjenbruch LONG TERM...Dankers AVIATION...Danielson
Hazardous Weather Outlook National Weather Service Denver/Boulder CO 1049 AM MST Wed Mar 6 2019 COZ030>051-071800- 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- 1049 AM MST Wed Mar 6 2019 ...WINTER STORM WARNING NORTHERN GORE RANGE AND RABBIT EARS PASS TODAY THROUGH THURSDAY AFTERNOON... ...WINTER WEATHER ADVISORY NORTH CENTRAL MOUNTAINS TODAY THROUGH THURSDAY AFTERNOON... This hazardous weather outlook is for northeast and north central Colorado. .DAY ONE...Today and Tonight Another round of heavy snow is on the way for the mountains. Periods of snow will occur in the Colorado high country today, with some rain developing in valley locations up to about 9000 feet. Slick and snow covered roads can be expected over the higher elevations today, but conditions will deteriorate considerably from west to east across the mountains this evening as a cold front arrives. This will bring a burst of heavy snow, poor visibilities, and difficult travel conditions. The brunt of this storm will likely reach the I-70 Mountain Corridor and Summit County 8 PM to 11 PM. Travel is not recommended in the high country this evening or overnight. In the lower elevations, scattered rain and snow showers will spread across the plains this evening with a chance of some brief light freezing rain as temperatures drop below freezing. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday Light to moderate snow is expected to continue in the mountains Thursday with some additional snowfall expected. Across lower elevations, expect a gradual warming through the end of the week, but temperatures will still be below normal. Another weather disturbance is expected to be moving into the mountains on Friday with more light to moderate snowfall. The plains could see some rain and snow showers Friday night and will have gusty winds on Saturday. Additional unsettled weather is expected on Monday and Tuesday. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed today or tonight.
The national radar mosaic for the moment the first event began.
2 winter storm, 2 winter weather, 1 avalanche. Local standard time, as filed.
An avalanche hit a portion of Interstate 70 and trapped several vehicles. No injuries were reported.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Colorado in 2019Every state in 2019This day in weather historyWarnings in Colorado, March 2019
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: 799963, 799964, 799965, 799966, 799967.