Brennan Linsley / AP

Tens of thousands smoke marijuana and listen to live music at the 420 pro-marijuana rally at Civic Center Park in Denver on Saturday. Gunshots later dispersed the crowd and injured two.

DENVER -- Three people were shot and wounded at a pro-marijuana rally on Saturday, disrupting the first celebration of a symbolic drug culture holiday since Colorado voters legalized the recreational use of pot.

A man and a woman were each shot in the leg and a youth was grazed by a bullet, but the wounds were not life-threatening, Denver police said on Twitter. Officers were looking for two suspects in the shootings, which occurred as the rally was winding down.

"I heard five or six gunshots in quick succession," said Cole Wagenknecht, 27, who attended the rally at a downtown park near the State Capitol. "That's why I knew it wasn't fireworks. Then everybody started to scatter and ran toward one end of the park."

The rally was one of a number of marijuana-related activities, including classes on hashish making and cooking with cannabis, held in Colorado on April 20 - within the drug culture, "4/20" and "420" are synonymous with marijuana use.

The shootings came at a sensitive time for Colorado marijuana activists, who are closely watching proposals from state lawmakers on the rules that will govern the sale of small amounts of pot to people 21 and older. In November, voters in Colorado and Washington state became the first in the country to approve recreational use of marijuana.

The federal government considers marijuana an illegal and dangerous narcotic. U.S. officials have said they are considering how to respond to the legalization moves.

Miguel Lopez, the organizer of the Denver rally, said the event was the "world's largest 4/20 rally," and would be bigger than in past years because of Colorado's legalization move.

"We had 60,000 people here last year and expect 75,000 to 80,000 this year," Lopez said before the event.

Police said attendance was lower than 80,000 but would not provide a crowd estimate.

Lopez said the rally was part of a "grassroots" effort to compel the federal government to stop prosecuting pot users.

Despite the passage of the Colorado legalization measure, it remains illegal under state law to use marijuana in public. Before the shootings, police officers were positioned across the street from the rally.

Denver police spokeswoman Raquel Lopez said she did not immediately have any details on possible arrests related to marijuana use at the rally.

Critics such as Denver city councilman Charlie Brown were not pleased with the pot rally.

"It's an embarrassment to the city," he said before the shootings. "It's the marijuana business in action and they're flouting the law." 

This story was originally published on Sat Apr 20, 2013 12:49 PM EDT

Austin Reed Sigg is charged in Jessica Ridgeway's death.

A Colorado teen pleaded not guilty Friday to murder and kidnapping in the kidnap-slaying and dismemberment of a 10-year-old girl that panicked Denver-area residents last fall — despite police testimony that the suspect confessed to the crime.

Austin Sigg, 18, stunned a courtroom by entering the not-guilty pleas in the death of Jessica Ridgeway in the Denver suburb of Westminster. Sigg also pleaded not guilty to a May attack on a 22-year-old jogger at a lake in Jessica's neighborhood.

Sigg's not-guilty pleas came despite his alleged confession and the discovery of some of the girl's remains at his home.

Jessica disappeared while walking to school on Oct. 5, leading parents to take extraordinary precautions to keep their children safe. Residents were encouraged to report suspicious behavior by neighbors.

If convicted, Sigg would face life in prison with the possibility of parole after 40 years. He cannot face the death penalty because he was 17 at the time of the slaying.

Sigg is charged with murder, kidnapping, sexual assault and robbery. Prosecutors added three counts of sexual exploitation of a child because child pornography was allegedly found during the investigation. Sigg denied to investigators that he sexually assaulted Jessica.

Jessica, a fifth-grader, disappeared after she left her house to meet a friend two blocks away on their way to school. Hundreds of police and residents searched for her, and parents escorted their children to and from school. The FBI asked residents to report suspicious behavior by friends, neighbors and even family members. Her torso was found in a secluded park Oct. 10.

A resident contacted authorities Oct. 19 to report Sigg because he reportedly had a fascination with death, Westminster police Detective Luis Lopez testified at a preliminary hearing. Two FBI agents took a DNA sample from Sigg. His mother called 911 on Oct. 23, saying he wanted to confess. Lopez said Sigg's DNA was found on Jessica's clothing.

Jessica Ridgeway

Investigators said Sigg told them that some of Jessica's remains were hidden in a crawl space in his mother's home, where he lived.

Detectives said he described how he abducted Jessica as she walked past his car, bound her arms and her legs, drove around for a little bit then took her to his house. There, he told investigators, he tried to strangle her and then used his hands to kill her. He also allegedly told investigators that he dismembered Jessica in a bathtub.

Lopez testified that Sigg attended a community college and took classes in mortuary sciences.

Jessica's father lives in the Kansas City, Mo., area. 

A vast storm system Wednesday night may bring snow from eastern South Dakota into northeast Nebraska, northwest Iowa, and central and southern Minnesota, to include the Twin Cities, The Weather Channel reported. Four to eight inches of snow could fall Wednesday night alone in the Sioux Falls to Minneapolis corridor.

Light snow could reach as far east as northern Wisconsin, The Weather Channel reported.

Farther east, in upstate New York, Buffalo could see a brief period of freezing rain Thursday morning.

Earlier Wednesday, the storm pounded the Dakotas with snow, coated Oklahoma with rare spring ice and took aim at parts of the Mid-Atlantic and South.

Snow, freezing rain and strong winds snapped trees, broke power poles and left cars sheathed in ice in South Dakota, and the city of Sioux Falls declared a state of emergency.

More coverage from weather.com

Farther south — and much more unusually — ice coated roads in Oklahoma, all the way down to the Red River border with Texas.

“For April, that is really amazing,” said Tom Niziol, a meteorologist and winter weather expert for The Weather Channel.

It all made for a messy day of travel in the Great Plains and the Midwest. Chicago O’Hare, a hub airport for the central United States, reported almost 500 flight cancellations.

Dirk Lammers / AP

Icy branches partially block a city street and fall amid parked cars in Sioux Falls, S.D.

As the storm system lumbers eastward, powerful thunderstorms are expected later Wednesday and overnight in Pennsylvania and Maryland, including Philadelphia and its suburbs.

It has been unusually cold this week in the West and unseasonably warm in the East, including temperatures pushing 90 degrees Wednesday in Washington. That warm air makes the weather system more dangerous.

“There will be more than enough fuel for these storms,” said Carl Parker, another meteorologist for The Weather Channel.

A line of late-day storms was expected to sweep across Arkansas on Wednesday afternoon, threatening to dump damaging hail and perhaps spawn tornadoes before pushing out of the state in the evening.

The same storm system has already produced bizarre weather elsewhere in the country.

Earlier this week, the temperature fell 55 degrees in Denver in less than 24 hours. Gusty wind nudged 21 cars of a freight train off the tracks in Nebraska. And snowflakes the size of cotton balls fall in Marshall, Minn., NBC affiliate KARE in Minneapolis reported.

This story was originally published on Wed Apr 10, 2013 6:32 AM EDT

Ed Andrieski / AP

Instructor Ted Smith, left, shows Ginger and Heath Grider how to cut and plant a section of a tomato plant during class at THC University at the Tivoli in Denver.

It may be called weed, but marijuana is legendarily hard to grow.

Now that the drug has been made legal in Washington and Colorado, growers face a dilemma. State-sanctioned gardening coaches can help folks cultivate tomatoes or zucchini, but both states have instructed them not to show people the best way to grow marijuana. The situation is similar in more than a dozen additional states that allow people to grow the drug with medical permission.

That's leaving some would-be marijuana gardeners looking to the private sector for help raising the temperamental plant.

"We can't go there," said Brian Clark, a spokesman for Washington State University in Pullman, which runs the state's extension services for gardening and agriculture. "It violates federal law, and we are a federally funded organization."

The issue came up because people are starting to ask master gardeners for help in growing cannabis, Clark said. Master gardeners are volunteers who work through state university systems to provide horticultural tips in their communities.

Related: Colorado, Washington approve recreational marijuana use

The situation is the same in Colorado, where Colorado State University in Fort Collins recently added a marijuana policy to its extension office, warning that any employee who provides growing assistance acts outside the scope of his or her job and "assumes personal liability for such action."

The growing predicament is just the latest quandary for these states that last year flouted federal drug law by removing criminal penalties for adults over 21 with small amounts of pot. In Washington, home-growing is banned, but it will be legal to grow pot commercially once state officials establish rules and regulations.

In Colorado, adults are allowed to grow up to six marijuana plants in their own homes, so long as they're in a locked location out of public view.

At least two Colorado entrepreneurs are taking advantage of that aspect of the law; they're offering growing classes that have attracted wannabe professional growers, current users looking to save money by growing their own pot and a few baby boomers who haven't grown pot in decades and don't feel comfortable going to a marijuana dispensary.

"We've been doing this on our own, but I wanted to learn to grow better," said Ginger Grinder, a medical marijuana patient from Portales, N.M., who drove to Denver for a "Marijuana 101" class she saw advertised online.

Grinder, a stay-at-home mom who suffers from lupus and fibromyalgia, joined about 20 other students earlier this month for a daylong crash course in growing the finicky marijuana plant.

Taught in a rented room at a public university, the course had students practicing on tomato plants because pot is prohibited on campus. The group took notes on fertilizer and fancy hydroponic growing systems, and snipped pieces of tomato plants to practice cloning, a common practice for nascent pot growers to start raising weed from a "mother" marijuana plant.

Related: Recreational marijuana users could get pot from vending machines, company says

Ted Smith, a longtime instructor at an indoor gardening shop, led the class, and warned these gardeners that their task won't be easy. Marijuana is fickle, he said. It's prone to mildews and molds, picky about temperature and pH level, intolerant to tap water.

A precise schedule is also a must, Smith warned, with set light and dark cycles and watering at the same time each day. Unlike many house plants, Smith warned, marijuana left alone for a long weekend can curl and die.

"Just like the military ... they need to know when they're getting their water and chow," Smith said of the plants.

The class was the brainchild of Matt Jones, a 24-year-old Web developer who wanted to get into the marijuana business without raising or selling it himself. As a teenager, Jones once tried to grow pot himself in empty Home Depot paint buckets. He used tap water and overwatered, and the marijuana wilted and died.

"It was a disaster," he recalled. Jones organized the class and an online "THC University" for home growers, but his own thumb isn't green. Jones said he'll be buying his marijuana from professional growers.

The course showed would-be grower Cael Nodd, a 34-year-old stagehand in Denver, that marijuana gardening can be an intimidating prospect.

"It seems like there's going to be a sizable investment," he said. "I want something that really tastes good. Doesn't seem like it will be that easy."

Handout / Reuters

James Holmes is seen in this undated police handout photo.

Updated at 6:44 a.m. ET: CENTENNIAL, Colo. - Accused Colorado theater gunman James Eagan Holmes was taken to the hospital on Tuesday for a medical condition that rendered him unable to attend a court hearing set for two days later, his lawyers told an emergency hearing on Wednesday.

The lawyers, explaining in vague terms the unspecified sudden developments they said caused his condition, requested a delay in a routine pre-trial hearing set for Thursday. There was no immediate word on Holmes' current condition.

"What occurred was mid-day yesterday. We were informed of a situation that involved a trip to a hospital," Holmes' attorney Tamara Brady said in court, giving scant further details but adding: "It's not as simple as a migraine."

Holmes, a 24-year-old former neuroscience graduate student, is accused of opening fire inside a suburban Denver movie theater during a midnight screening of the movie "The Dark Knight Rises" in July, killing 12 people and wounding 58 others.

The Aurora, Colo., rampage was one of the bloodiest acts of gun violence in the United States in recent years.

Holmes' attorneys filed an emergency motion earlier on Wednesday seeking to delay a pre-trial hearing in his case, citing the unspecified new condition that has left him unable to appear in court.

A judge approved the motion and set a new hearing for December 10. Holmes' attorneys did not provide further details in their motion, citing legal, medical, and psychological privilege.

"As a result of developments over the past 24 hours, Mr. Holmes is in a condition that renders him unable to be present in court for tomorrow's hearing," Holmes' lawyers wrote in the delay motion.

Another of Holmes' attorneys, public defender Daniel King, did not respond to reporters who asked if Holmes was still in the hospital.

Prosecutors had objected to the motion, saying it should be denied unless more detailed information was provided on Holmes' condition than was contained in the defense request.

"It is not clear whether it is claimed he is suffering from a physical medical condition, a mental condition, whether he is suffering from a negative emotional reaction to his circumstances, or anything other than he has some kind of 'condition,'" prosecutors wrote in their response.

Prosecutors have previously depicted Holmes as a young man whose once promising academic career was in tatters at the time of the shooting. He failed oral board exams for graduate school in June and a professor suggested he may not have been a good fit for his competitive doctorate program.

Holmes then began a voluntary withdrawal from the school and amassed an arsenal of weapons as part of "a detailed and complex" plan to commit mass murder, prosecutors charge.

Holmes has yet to enter a plea in the case, and prosecutors have not indicated whether they will seek the death penalty.

Holmes' lawyers, who analysts have suggested may be laying the groundwork for an insanity defense, have said Holmes suffers from mental illness and sought to get help before the shooting.

Arapahoe County Sheriff Grayson Robinson, asked about Holmes' condition, told Reuters he could not release any information, citing privacy issues and jail security. Holmes was being held at the Arapahoe County jail.

More content from NBCNews.com:

• Obama: GOP criticism of UN ambassador over Benghazi attack is 'outrageous'
• In 911 calls, Kelley tries to invoke diplomatic immunity
• Etan Patz suspect indicted on murder, kidnapping charges, sources say
• 'I got the wrong Courtney': Man picks up incorrect girl from school
• Storm system could snarl East Coast holiday travel

Follow US news from NBCNews.com on Twitter and Facebook