Major Earthquake In Haiti

A class "major" earthquake of magnitude 7.0 struck 10 miles Southwest of Port-au-Prince, Haiti Tuesday night at 4:53 p.m. local time, shortly before dark fell over the Caribbean island of Hispaniola. This earthquake was pretty much a worst-case-scenario because of several factors. The initial 7.0 was shallow, only 6.2 miles deep. Also, it was devastatingly close to the highest population density in the affected region, the capital of Haiti. Finally, this was a "strike-slip" type of earthquake, where two plates slide past each other in a horizontal fashion instead of one being uplifted by the other.

When this happens, buildings are shaken side-to-side instead of up and down. This type of horizontal shaking of a structure usually leads to building failure, as the weight of the roof causes an implosion and walls collapse. In Haiti, most buildings are not reinforced concrete, and not earthquake-resistant. This likely means many structures failed in the initial earthquake. If they did not do so in that first major quake, they probably later collapsed during one of the 35 aftershocks (as of 10 a.m.) that occurred overnight, 14 of which were magnitude 5.0 or greater. You can see a full list of all the earthquakes and aftershocks here. The initial 7.0 was felt in the surrounding countries in the Caribbean, as displayed here on the Shake Map:

For your reference, here are the classes of earthquakes on the Richter Scale, with the strength of the earthquake felt increasing logarithmically:

This part of the Caribbean has several fault lines running through it, which makes it particularly prone to seismic activity:

Weekend Outlook

We are watching for a potential storm system this weekend that will develop along the Gulf Coast at the end of the week, then track northeast along the southeast Atlantic Coast toward Virginia late Saturday night into Sunday. The track of this low is still uncertain, but it does appear from the latest data that it will move close enough to the Commonwealth to bring us a chance for rain Sunday. Depending on the timing and proximity of the low, precipitation type could be an issue. At this time, it appears rain will be the primary mode, but with surface temperatures expected to be near freezing Sunday morning, there is at least the potential for some icy spots if rain has already begun falling early Sunday. This is a forecast snapshot of Sunday morning with the approaching low from the south:

Depending on the timing of the rain's arrival, temperatures may have already risen back above freezing Sunday morning by the time it begins raining. Or, if the system accelerates into the region sooner, temperatures could still be around freezing when rain begins. Thus, precipitation type will depend on the track and timing of this system. We will provide updates through the week as the storm develops along the Gulf Coast and heads northeast.

Warming Trend This Week

Richmond recorded its coldest low temperature of the season today with a low of 13 degrees. This is coldest it's been since March 4, 2009, when RIC dropped to 10 degrees. If you're not a fan of this kind of cold, here's some good news for your Monday morning. A gradual warming trend is anticipated this week for much of the Southeastern U.S., a great thaw for places that have been in a deep freeze for nearly two weeks. A slew of record low temperatures continue to be broken in Florida. Here are Monday's new record lows in the Shivering--I mean Sunshine--State:
Tallahassee 14 degrees
Jacksonville 17 degrees
Gainesville 17 degrees
Lakeland 23 degrees
Tampa 25 degrees
Orlando 29 degrees
Fort Myers 31 degrees
West Palm Beach 33 degrees
Miami 36 degrees
Key West 42 degrees (Interesting note: This is the 2nd coldest temperature ever recorded in Key West, with the coldest temperature being 41 degrees, which has only occurred twice!)

High pressure will build into the Southeast and Mid-Atlantic mid-week:

Under this ridge, Central Virginia will break 50-degrees in some spots by Wednesday, with others following suit Thursday and Friday. Richmond's warmest high temperature this month has been 43 degrees, which occurred on both the 1st and 6th. The last time Richmond International Airport recorded a high 50+ was December 27th, when we topped out at 53 degrees. We have also been below freezing every night since Dec 26th. Next Sunday morning, Richmond's low temperature looks like it will stay above the freezing mark.