diff --git a/internal/mock/generator.py b/internal/mock/generator.py
new file mode 100755
index 000000000..08d238c38
--- /dev/null
+++ b/internal/mock/generator.py
@@ -0,0 +1,149 @@
+#!/usr/bin/env python
+"""
+Generates alerts and sends to Alertmanager API.
+
+1. Start Alertmanager:
+
+$ docker run \
+    --rm \
+    --name prom \
+    -p 9093:9093 \
+    -v $(pwd)/alertmanager.yml:/etc/alertmanager/alertmanager.yml \
+    prom/alertmanager
+
+2. Start this script
+3. Start karma:
+
+$ karma \
+    --alertmanager.uri http://localhost:9093 \
+    --alertmanager.interval 10s \
+    --annotations.hidden help \
+    --labels.color.unique "@receiver instance cluster" \
+    --labels.color.static job \
+    --filters.default "@receiver=by-cluster-service"
+"""
+
+
+import random
+import json
+import time
+import urllib2
+
+
+API = "http://localhost:9093"
+
+
+def jsonPostRequest(uri, data):
+    req = urllib2.Request(uri)
+    req.add_header("Content-Type", "application/json")
+    response = urllib2.urlopen(req, json.dumps(data))
+
+
+def addSilence(matchers, startsAt, endsAt, createdBy, comment):
+    jsonPostRequest("{}/api/v1/silences".format(API), {
+        "matchers": matchers,
+        "startsAt": startsAt,
+        "endsAt": endsAt,
+        "createdBy": createdBy,
+        "comment": comment
+    })
+
+
+def addAlerts(alerts):
+    jsonPostRequest("{}/api/v1/alerts".format(API), alerts)
+
+
+def newMatcher(name, value, isRegex):
+    return {"name": name, "value": value, "isRegex": isRegex}
+
+
+def newAlert(labels, annotations=None, generatorURL="http://localhost:9093"):
+    return {
+        "labels": labels,
+        "annotations": annotations or {},
+        "generatorURL": generatorURL
+    }
+
+
+class AlertGenerator(object):
+    name = "Fake Alert"
+
+    def __init__(self, interval=15):
+        self._interval = interval
+        self._lastSend = 1
+
+    def _labels(self, **kwargs):
+        labels = {"alertname": self.name}
+        labels.update(kwargs)
+        return labels
+
+    def _send(self):
+        alerts = self.generate()
+        if alerts:
+            print("{} sending {} alert(s)".format(self.name, len(alerts)))
+            addAlerts(alerts)
+
+    def tick(self):
+        if time.time() - self._lastSend >= self._interval:
+            self._send()
+            self._lastSend = time.time()
+
+
+class AlwaysOnAlert(AlertGenerator):
+    name = "Always On Alert"
+
+    def generate(self):
+        return [
+            newAlert(
+                self._labels(instance="server{}".format(i))
+            ) for i in xrange(0, 10)
+        ]
+
+
+class RandomInstances(AlertGenerator):
+    name = "Random Instances"
+
+    def generate(self):
+        instances = random.randint(0, 30)
+        return [
+            newAlert(
+                self._labels(instance="server{}".format(i))
+            ) for i in xrange(0, instances)
+        ]
+
+
+class LowChance(AlertGenerator):
+    name = "Low Chance"
+
+    def generate(self):
+        throw = random.randint(0, 100)
+        if throw > 10:
+            return []
+        return [
+            newAlert(
+                self._labels(instance="server{}".format(i))
+            ) for i in xrange(0, 3)
+        ]
+
+
+class TimeAnnotation(AlertGenerator):
+    name = "Time Annotation"
+
+    def generate(self):
+        annotations = {"time": str(int(time.time()))}
+        return [
+            newAlert(self._labels(instance="server1"), annotations)
+        ]
+
+
+if __name__ == "__main__":
+    generators = [
+        AlwaysOnAlert(15),
+        RandomInstances(30),
+        LowChance(60),
+        TimeAnnotation(5),
+    ]
+    while True:
+        for g in generators:
+            g.tick()
+        time.sleep(1)
diff --git a/ui/src/Components/Grid/AlertGrid/AlertGroup/Alert/AlertMenu.js b/ui/src/Components/Grid/AlertGrid/AlertGroup/Alert/AlertMenu.js
index eadb02bdd..7ac4e5446 100644
--- a/ui/src/Components/Grid/AlertGrid/AlertGroup/Alert/AlertMenu.js
+++ b/ui/src/Components/Grid/AlertGrid/AlertGroup/Alert/AlertMenu.js
@@ -38,12 +38,6 @@ const MenuContent = onClickOutside(
         style={popperStyle}
         data-placement={popperPlacement}
       >
-        <div
-          className="dropdown-item cursor-pointer"
-          onClick={() => onSilenceClick(silenceFormStore, group, alert)}
-        >
-          <FontAwesomeIcon icon={faBellSlash} /> Silence this alert
-        </div>
         <h6 className="dropdown-header">Alert source links:</h6>
         {alert.alertmanager.map(am => (
           <a
@@ -57,6 +51,13 @@ const MenuContent = onClickOutside(
             {am.name}
           </a>
         ))}
+        <div className="dropdown-divider" />
+        <div
+          className="dropdown-item cursor-pointer"
+          onClick={() => onSilenceClick(silenceFormStore, group, alert)}
+        >
+          <FontAwesomeIcon icon={faBellSlash} /> Silence this alert
+        </div>
       </div>
     );
   }
diff --git a/ui/src/Components/Grid/AlertGrid/AlertGroup/Alert/AlertMenu.test.js b/ui/src/Components/Grid/AlertGrid/AlertGroup/Alert/AlertMenu.test.js
index 963e67be6..d8bca5f3d 100644
--- a/ui/src/Components/Grid/AlertGrid/AlertGroup/Alert/AlertMenu.test.js
+++ b/ui/src/Components/Grid/AlertGrid/AlertGroup/Alert/AlertMenu.test.js
@@ -70,7 +70,7 @@ const MountedMenuContent = group => {
 describe("<MenuContent />", () => {
   it("clicking on 'Silence' icon opens the silence form modal", () => {
     const tree = MountedMenuContent(group);
-    const button = tree.find(".dropdown-item").at(0);
+    const button = tree.find(".dropdown-item").at(1);
     button.simulate("click");
     expect(silenceFormStore.toggle.visible).toBe(true);
   });
diff --git a/ui/src/Components/Grid/AlertGrid/AlertGroup/Silence/index.js b/ui/src/Components/Grid/AlertGrid/AlertGroup/Silence/index.js
index a265583e9..40742cb7f 100644
--- a/ui/src/Components/Grid/AlertGrid/AlertGroup/Silence/index.js
+++ b/ui/src/Components/Grid/AlertGrid/AlertGroup/Silence/index.js
@@ -34,7 +34,7 @@ SilenceComment.propTypes = {
   silence: PropTypes.object.isRequired
 };
 
-const SilenceExpiryBadgeWithProgress = ({ silence }) => {
+const SilenceExpiryBadgeWithProgress = ({ silence, progress }) => {
   // if silence is expired we can skip progress value calculation
   if (moment(silence.endsAt) < moment()) {
     return (
@@ -44,15 +44,10 @@ const SilenceExpiryBadgeWithProgress = ({ silence }) => {
     );
   }
 
-  const durationDone = moment().unix() - moment(silence.startsAt).unix();
-  const durationTotal =
-    moment(silence.endsAt).unix() - moment(silence.startsAt).unix();
-  const durationPercent = (durationDone / durationTotal) * 100;
-
   let progressClass;
-  if (durationPercent > 90) {
+  if (progress > 90) {
     progressClass = "progress-bar bg-danger";
-  } else if (durationPercent > 75) {
+  } else if (progress > 75) {
     progressClass = "progress-bar bg-warning";
   } else {
     progressClass = "progress-bar bg-success";
@@ -65,8 +60,8 @@ const SilenceExpiryBadgeWithProgress = ({ silence }) => {
         <div
           className={progressClass}
           role="progressbar"
-          style={{ width: durationPercent + "%" }}
-          aria-valuenow={durationPercent}
+          style={{ width: progress + "%" }}
+          aria-valuenow={progress}
           aria-valuemin="0"
           aria-valuemax="100"
         />
@@ -75,7 +70,8 @@ const SilenceExpiryBadgeWithProgress = ({ silence }) => {
   );
 };
 SilenceExpiryBadgeWithProgress.propTypes = {
-  silence: PropTypes.object.isRequired
+  silence: PropTypes.object.isRequired,
+  progress: PropTypes.number.isRequired
 };
 
 const SilenceDetails = ({ alertmanager, silence }) => {
@@ -164,12 +160,34 @@ const Silence = inject("alertStore")(
         { name: "Silence collpase toggle" }
       );
 
-      componentDidUpdate() {
-        const { afterUpdate } = this.props;
-        afterUpdate();
+      progress = observable(
+        {
+          value: 0,
+          calculate(startsAt, endsAt) {
+            const durationDone = moment().unix() - moment(startsAt).unix();
+            const durationTotal =
+              moment(endsAt).unix() - moment(startsAt).unix();
+            const durationPercent = Math.floor(
+              (durationDone / durationTotal) * 100
+            );
+            if (this.value !== durationPercent) {
+              this.value = durationPercent;
+            }
+          }
+        },
+        {
+          calculate: action.bound
+        }
+      );
+
+      constructor(props) {
+        super(props);
+
+        this.recalculateProgress();
+        this.progressTimer = setInterval(this.recalculateProgress, 30 * 1000);
       }
 
-      render() {
+      getSilence = () => {
         const { alertStore, alertmanager, silenceID } = this.props;
 
         // We pass alertmanager name and silence ID to Silence component
@@ -177,16 +195,36 @@ const Silence = inject("alertStore")(
         // Data might be missing from the store so first check if we have
         // anything for this alertmanager instance
         const amSilences = alertStore.data.silences[alertmanager.name];
-        if (!amSilences)
-          return (
-            <FallbackSilenceDesciption
-              alertmanager={alertmanager}
-              silenceID={silenceID}
-            />
-          );
+        if (!amSilences) return null;
 
         // next check if alertmanager has our silence ID
         const silence = amSilences[silenceID];
+        if (!silence) return null;
+
+        return silence;
+      };
+
+      recalculateProgress = () => {
+        const silence = this.getSilence();
+        if (silence !== null) {
+          this.progress.calculate(silence.startsAt, silence.endsAt);
+        }
+      };
+
+      componentDidUpdate() {
+        const { afterUpdate } = this.props;
+        afterUpdate();
+      }
+
+      componentWillUnmount() {
+        clearInterval(this.progressTimer);
+        this.progressTimer = null;
+      }
+
+      render() {
+        const { alertmanager, silenceID } = this.props;
+
+        const silence = this.getSilence();
         if (!silence)
           return (
             <FallbackSilenceDesciption
@@ -213,7 +251,10 @@ const Silence = inject("alertStore")(
                     {silence.createdBy}
                   </cite>
                   {this.collapse.value ? (
-                    <SilenceExpiryBadgeWithProgress silence={silence} />
+                    <SilenceExpiryBadgeWithProgress
+                      silence={silence}
+                      progress={this.progress.value}
+                    />
                   ) : null}
                 </span>
               </span>
diff --git a/ui/src/Components/Grid/AlertGrid/AlertGroup/Silence/index.test.js b/ui/src/Components/Grid/AlertGrid/AlertGroup/Silence/index.test.js
index 4eb9b29de..dd23a3930 100644
--- a/ui/src/Components/Grid/AlertGrid/AlertGroup/Silence/index.test.js
+++ b/ui/src/Components/Grid/AlertGrid/AlertGroup/Silence/index.test.js
@@ -1,5 +1,6 @@
 import React from "react";
 
+import { toJS } from "mobx";
 import { Provider } from "mobx-react";
 
 import { mount, shallow } from "enzyme";
@@ -9,7 +10,7 @@ import toDiffableHtml from "diffable-html";
 import { advanceTo, clear } from "jest-date-mock";
 
 import { AlertStore } from "Stores/AlertStore";
-import { Silence, SilenceDetails, SilenceExpiryBadgeWithProgress } from ".";
+import { Silence, SilenceDetails } from ".";
 
 const mockAfterUpdate = jest.fn();
 
@@ -150,6 +151,14 @@ describe("<Silence />", () => {
     expect(link).toHaveLength(1);
     expect(link.text()).toBe("Fake silence");
   });
+
+  it("clears progress timer on unmount", () => {
+    const tree = MountedSilence().find("Silence");
+    const instance = tree.instance();
+    expect(instance.progressTimer).toBeTruthy();
+    instance.componentWillUnmount();
+    expect(instance.progressTimer).toBeNull();
+  });
 });
 
 const ShallowSilenceDetails = () => {
@@ -173,27 +182,37 @@ describe("<SilenceDetails />", () => {
   });
 });
 
-const ShallowSilenceExpiryBadgeWithProgress = () => {
-  return shallow(<SilenceExpiryBadgeWithProgress silence={silence} />);
-};
-
 describe("<SilenceExpiryBadgeWithProgress />", () => {
   it("renders with class 'danger' and no progressbar when expired", () => {
     advanceTo(new Date(2001, 0, 1, 23, 0, 0));
-    const tree = ShallowSilenceExpiryBadgeWithProgress();
+    const tree = MountedSilence();
     expect(tree.html()).toMatch(/badge-danger/);
-    expect(tree.text()).toBe("Expired <t />");
+    expect(tree.text()).toMatch(/Expired a year ago/);
   });
 
   it("progressbar uses class 'danger' when > 90%", () => {
     advanceTo(new Date(2000, 0, 1, 19, 30, 0));
-    const tree = ShallowSilenceExpiryBadgeWithProgress();
+    const tree = MountedSilence();
     expect(tree.html()).toMatch(/progress-bar bg-danger/);
   });
 
   it("progressbar uses class 'danger' when > 75%", () => {
     advanceTo(new Date(2000, 0, 1, 17, 45, 0));
-    const tree = ShallowSilenceExpiryBadgeWithProgress();
+    const tree = MountedSilence();
     expect(tree.html()).toMatch(/progress-bar bg-warning/);
   });
+
+  it("calling calculate() on progress multiple times in a row doesn't change the value", () => {
+    const startsAt = new Date(2000, 0, 1, 10, 0, 0);
+    const endsAt = new Date(2000, 0, 1, 20, 0, 0);
+
+    const tree = MountedSilence().find("Silence");
+    const instance = tree.instance();
+
+    const value = toJS(instance.progress.value);
+    instance.progress.calculate(startsAt, endsAt);
+    instance.progress.calculate(startsAt, endsAt);
+    instance.progress.calculate(startsAt, endsAt);
+    expect(toJS(instance.progress.value)).toBe(value);
+  });
 });
diff --git a/ui/src/Components/SilenceModal/SilenceForm.js b/ui/src/Components/SilenceModal/SilenceForm.js
index b71384f35..9bdcf0ca3 100644
--- a/ui/src/Components/SilenceModal/SilenceForm.js
+++ b/ui/src/Components/SilenceModal/SilenceForm.js
@@ -75,6 +75,9 @@ const SilenceForm = observer(
     componentDidMount() {
       const { silenceFormStore, settingsStore } = this.props;
 
+      // reset startsAt & endsAt on every mount
+      silenceFormStore.data.resetStartEnd();
+
       if (silenceFormStore.data.matchers.length === 0) {
         silenceFormStore.data.addEmptyMatcher();
       }
diff --git a/ui/src/Components/SilenceModal/SilenceModalContent.js b/ui/src/Components/SilenceModal/SilenceModalContent.js
index 038307d90..a975870ff 100644
--- a/ui/src/Components/SilenceModal/SilenceModalContent.js
+++ b/ui/src/Components/SilenceModal/SilenceModalContent.js
@@ -14,7 +14,8 @@ const SilenceModalContent = observer(
     static propTypes = {
       alertStore: PropTypes.object.isRequired,
       silenceFormStore: PropTypes.object.isRequired,
-      settingsStore: PropTypes.object.isRequired
+      settingsStore: PropTypes.object.isRequired,
+      onHide: PropTypes.func.isRequired
     };
 
     componentDidMount() {
@@ -26,7 +27,12 @@ const SilenceModalContent = observer(
     }
 
     render() {
-      const { alertStore, silenceFormStore, settingsStore } = this.props;
+      const {
+        alertStore,
+        silenceFormStore,
+        settingsStore,
+        onHide
+      } = this.props;
 
       return ReactDOM.createPortal(
         <div className="modal d-block bg-primary-transparent-80" role="dialog">
@@ -34,11 +40,7 @@ const SilenceModalContent = observer(
             <div className="modal-content">
               <div className="modal-header">
                 <h5 className="modal-title">Add new silence</h5>
-                <button
-                  type="button"
-                  className="close"
-                  onClick={silenceFormStore.toggle.hide}
-                >
+                <button type="button" className="close" onClick={onHide}>
                   <span className="align-middle">&times;</span>
                 </button>
               </div>
diff --git a/ui/src/Components/SilenceModal/index.js b/ui/src/Components/SilenceModal/index.js
index 77c24c20b..5ada556d4 100644
--- a/ui/src/Components/SilenceModal/index.js
+++ b/ui/src/Components/SilenceModal/index.js
@@ -18,6 +18,18 @@ const SilenceModal = observer(
       settingsStore: PropTypes.object.isRequired
     };
 
+    toggleModal = () => {
+      const { silenceFormStore } = this.props;
+
+      silenceFormStore.toggle.toggle();
+      if (silenceFormStore.toggle.visible === false) {
+        // need to reset progress if we're hiding modal
+        // SilenceSubmitProgress sends a fetch on mount which would result in
+        // duplicate silences if we didn't reset state of the form on destroy
+        silenceFormStore.data.resetProgress();
+      }
+    };
+
     componentDidUpdate() {
       const { silenceFormStore } = this.props;
 
@@ -37,10 +49,7 @@ const SilenceModal = observer(
       return (
         <React.Fragment>
           <li className="nav-item">
-            <a
-              className="nav-link cursor-pointer"
-              onClick={silenceFormStore.toggle.toggle}
-            >
+            <a className="nav-link cursor-pointer" onClick={this.toggleModal}>
               <FontAwesomeIcon icon={faBellSlash} />
             </a>
           </li>
@@ -49,6 +58,7 @@ const SilenceModal = observer(
               alertStore={alertStore}
               silenceFormStore={silenceFormStore}
               settingsStore={settingsStore}
+              onHide={this.toggleModal}
             />
           ) : null}
         </React.Fragment>
diff --git a/ui/src/Components/SilenceModal/index.test.js b/ui/src/Components/SilenceModal/index.test.js
index ad858cf0e..b1aa3d359 100644
--- a/ui/src/Components/SilenceModal/index.test.js
+++ b/ui/src/Components/SilenceModal/index.test.js
@@ -93,4 +93,13 @@ describe("<SilenceModal />", () => {
     tree.unmount();
     expect(document.body.className.split(" ")).not.toContain("modal-open");
   });
+
+  it("inProgress is set to false after modal is hidden", () => {
+    silenceFormStore.toggle.visible = true;
+    const tree = MountedSilenceModal();
+    silenceFormStore.data.inProgress = true;
+    const toggle = tree.find("button.close");
+    toggle.simulate("click");
+    expect(silenceFormStore.data.inProgress).toBe(false);
+  });
 });
diff --git a/ui/src/Stores/SilenceFormStore.js b/ui/src/Stores/SilenceFormStore.js
index a78e198cd..e8f993619 100644
--- a/ui/src/Stores/SilenceFormStore.js
+++ b/ui/src/Stores/SilenceFormStore.js
@@ -69,6 +69,11 @@ class SilenceFormStore {
         return true;
       },
 
+      resetStartEnd() {
+        this.startsAt = moment();
+        this.endsAt = moment().add(1, "hour");
+      },
+
       resetProgress() {
         this.inProgress = false;
         this.wasValidated = false;
@@ -193,6 +198,7 @@ class SilenceFormStore {
       }
     },
     {
+      resetStartEnd: action.bound,
       resetProgress: action.bound,
       addEmptyMatcher: action.bound,
       deleteMatcher: action.bound,
diff --git a/ui/src/Stores/SilenceFormStore.test.js b/ui/src/Stores/SilenceFormStore.test.js
index f7566f069..fab7d93b0 100644
--- a/ui/src/Stores/SilenceFormStore.test.js
+++ b/ui/src/Stores/SilenceFormStore.test.js
@@ -45,6 +45,16 @@ const MockGroup = () => {
 };
 
 describe("SilenceFormStore.data", () => {
+  it("resetStartEnd() sets startsAt and endsAt to defaults", () => {
+    store.data.startsAt = moment([2000, 1, 1, 0, 1, 0]);
+    store.data.endsAt = moment([2000, 1, 1, 1, 2, 0]);
+    expect(store.data.startsAt.isSame([2000, 1, 1], "day")).toBe(true);
+    expect(store.data.endsAt.isSame([2000, 1, 1], "day")).toBe(true);
+    store.data.resetStartEnd();
+    expect(store.data.startsAt.isSame([2000, 1, 1], "day")).toBe(false);
+    expect(store.data.endsAt.isSame([2000, 1, 1], "day")).toBe(false);
+  });
+
   it("resetProgress() sets 'inProgress' to false", () => {
     store.data.inProgress = true;
     expect(store.data.inProgress).toBe(true);